- Email: [email protected]
O43. Induction of apoptosis in laryngeal cancer cells by a compound isolated from Pteris semipinnata L.
Oral AbstractsPoster ListOrals ListPan. Disc. & Symp. Abs.Keynote Abs.Keynote Bios.ProgramIAOOWelcomeCommittee Listings
70
Oral abstracts / Oral Oncology Supplement 3 (2009) 56–122
identify molecular markers predicting the clinical behaviour of OSCC and SGT. In particular, the project attempts to disclose prognostic markers capable of defining the clinical course of three discrete classes of patients: those with early stage T1–T2 OSCC with unexpected aggressive behaviour; young patients (<40 years) affected by OSCC and lacking overt risk factors; and patients affected by metastatic SGT. Methods: In selected primary and metastatic lesions of OSCC we examined, at both mRNA and protein levels, the expression pattern of an apparently OSCC-enriched p63 variant and the 12 currently known cell surface-associated proteoglycans (NG2, syndecans-1-4 and glypicans-1-6). We evaluated these previously identified putative biomarkers both qualitatively and quantitatively and correlate their expression patterns with the clinical course of the patients. In parallel, we performed whole-genome comparative genetic screenings on primary lesions from metastatic and non-metastatic patients and secondary lesions of post-surgical patients. Both intact tumour samples and laser microdissected specimens were examined. These experimental approaches have been combined with hierarchical agglomerative clustering of previously identified gene markers through current bioinformatic algorithms and dedicated software tools. Expected results: We expect to reveal novel prognostic markers capable of predicting the unfavourable clinical course of early stage (T1–T2) OSCC patients, young (<40 years) OSCC patients lacking risk factors and individuals developing SGT. These molecular tools are instrumental for the clinical management and design of more tailored and individualized post-surgical treatments of subjects affected by these tumours. doi:10.1016/j.oos.2009.06.125
O41. Can SLUG, SNAI1, TWIST1, TGFß, N-cadherin and E-cadherin predict the metastatic potential of oral squamous cell carcinoma? E. Barker a,b, P. Reis b,*, M. Sukhai b, R. Goswami b, J. Irish a, S. Kamel-Reid b a b
Princess Margaret Hospital, Toronto, Canada The Ontario Cancer Institute, The University of Toronto, Canada
Introduction: Metastasis is a complex, multi-step process allowing primary tumours to spread to both regional and distant sites. Oral squamous cell carcinoma (OSCC) has significant potential for regional metastatic spread. The treatment of clinically node negative (cN0) necks remains controversial. A diagnostic test that could accurately predict the metastatic potential of OSCC would help define the appropriate treatment option for individual tumours. TWIST1, SNAI1 and SLUG are transcription factors that have shown to be dysregulated in aggressive human tumours. TGF-b is a growth factor also associated with poor clinical outcome. Both N-cadherin and E-cadherin are central in epithelial-mesenchymal transition. We hypothesised that SLUG, SNAI1, TWIST1, TGF-b, N-cadherin and E-cadherin could be used in combination to predict the metastatic potential of OSCC. Method: Fresh OSCC tumour samples [total = 48 patients; n = 24 N0; n = 24 (node positive) N+; n = 26 tongue; n = 17 floor of mouth (FOM); n = 5 other sites] and corresponding adjacent normal tissues (n = 21) were used for gene expression and protein analysis. Quantitative real-time RT-PCR was undertaken, TWIST1, SLUG, SNAI1, TGF-b, N-cadherin and E-cadherin expression quantified, using the Delta Delta Ct method, and correlated with protein expression as well as clinical and pathological parameters. Results: All genes were significantly differentially expressed, between adjacent normal tissue and the primary malignancy, independent of node status or primary site. When anatomical sites
were grouped, gene expression levels were significantly different for TWIST1 between N0 and N+ patients. When the ‘tongue’ sub site was analysed separately, both TWIST1 and SNAI1 had significantly reduced expression levels in the N+ patients compared with N0 patients. Protein levels are currently being analysed and will be correlated with expression data and presented. Conclusion: A combination of genes offers a potential genetic signature to predict the clinical course of OSCC. doi:10.1016/j.oos.2009.06.126
O42. Mcl-1 expression is associated with pathogenesis and radiotherapy treatment response in chewing tobacco-associated oral carcinomas T.R. Teni a,*, S. Mallick a, V. Palve a, S. Pawar a, R. Patil c, J.P. Agarwal b a
Advanced Centre for Treatment, Research and Education in Cancer (ACTREC) Kharghar, Navi Mumbai-410210, India b Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai 4000 12, India c Sharad Pawar Dental College, Wardha, India Expression of Bcl-2 family proteins in tumours can modulate apoptosis, influencing tumour behaviour and treatment. To investigate their role in oral tumorigenesis, nine Bcl-2 family transcripts were examined in three oral cell lines and 25 oral tumours using a Ribonuclease Protection Assay. Mcl-1 splice variants were assessed by RT-PCR and Mcl-1 protein was studied in normal, premalignant and malignant oral tissues and cell lines by immunohistochemistry and/or immunoblotting. A further 39 oral tumours prior to primary radiotherapy were assessed for expression of a set of proteins – Mcl-1, bclxl, p53, survivin and PCNA. The cell lines exhibited significantly higher levels of 7/9 Bcl-2 family transcripts as compared with those in normal tongue, and significantly higher (p = 0.030, p = 0.004) anti-apoptotic versus pro-apoptotic transcripts. Elevated Mcl-1 mRNA was observed in 11/25 (44%) tumours as compared with normal tissues with a five to tenfold higher expression of full length anti-apoptotic Mcl-1 transcript versus the pro-apoptotic short isoform. Strong cytoplasmic Mcl-1 immunoreactivity was detected predominantly in differentiated epithelia in 27/33 (82%) oral tumours, 18/20 (90%) leukoplakia, 25/30 (83%) submucous fibrosis, 3/3 oral cell lines, with weak staining in 8/15 (53%) normal mucosa samples. Mcl-1 positivity in malignant and premalignant tissues was comparable but significantly higher (p < 0.01) than that in normal mucosa. High expression of PCNA and Mcl-1 in oral tumours correlated significantly (p = 0.007), (p = 0.05) with poor disease free survival as compared with low expression respectively and were independent prognostic factors for predicting DFS. Our studies thus suggest an important role for Mcl-1 early in oral cancer pathogenesis in protecting cells from apoptosis via neutralization of pro-apoptotic members and could be a potential therapeutic target for oral cancers. Analysis of PCNA and Mcl-1 levels may be useful in predicting the clinical response in oral cancer patients receiving primary radiotherapy. doi:10.1016/j.oos.2009.06.127
O43. Induction of apoptosis in laryngeal cancer cells by a compound isolated from Pteris semipinnata L. G.G. Chen *, C.S. Lo, H.C. Liu, A.C. Vlantis, M.C.T. Tone, C.A. van Hasselt The Chinese University of Hong Kong, Hong Kong
Purpose: Apoptosis has been involved in the killing mechanism of a number of anti-cancer agents. Although the efficiency of chemotherapy for laryngeal cancer has been improved recently, we still lack an effective therapeutic protocol to improve the life quality of patients. In search of novel therapeutic agents, we have identified a compound (5F) from herb medicine, Pteris semipinnata L., which possesses a strong ability to induce apoptosis of tumor cells. Methods: Laryngeal cancer cells with or without human papillomavirus 16 (HPV16) or 18 (HPV18) were treated with 5F for 24–72 h. At the end of treatment, cell proliferation and apoptosis were measured. A number of apoptotic molecules were explored to identify the target molecules. Results: 5F markedly reduced the proliferation of tumor cells treated by 7F. A significant number of cells were found to be apoptotic. It was noted that the percentage of reduced proliferation did not correlate with apoptosis, suggesting that cell death may be involved in other death models. Nevertheless, apoptosis appears to be a major target in the 5F-mediated cell death pathway. We also found that laryngeal cancer with HPV infection was less sensitive to 5F treatment, indicating that HPV may protect tumor cells from apoptosis. Such a protective effect of HPV was removed when the nuclear factor kappaB was inhibited, suggesting that a positive relationship between HPV infection and the activity of nuclear factor kappaB. The findings also lead to a concept that the inhibitors of nuclear factor kappa B would enhance the anti-tumor effect of 5F in laryngeal cancer. Conclusions: 5F is an effective agent to induce apoptosis of laryngeal cancer and the killing effect can be enhanced when the activity of nuclear factor kappa B is inhibited. doi:10.1016/j.oos.2009.06.128
O44. MAGE-A antigens in oral squamous cell carcinoma U.D.A. Müller-Richter a,*, T. Reuther a, S. Rauthe b, S. Gattenlöhner b, A.C. Kübler a a Department of Oral and Maxillofacial Plastic Surgery, Universityhospital Würzburg, Germany b Institute of Pathology, Universityhospital Würzburg, Germany
Background: Oral squamous cell carcinoma is amongst the most common malignancies. Despite all the efforts of the last decades prognosis is still unfavourable. To improve treatment options and prognosis further characterization of this malignancy is mandatory. MAGE-A antigens, a subgroup of cancer/testis antigens, are exclusively expressed on malignant transformed cells. Their role and their importance in oral squamous cell carcinoma have to be explored as they might be used as tumor markers or targets in immunotherapy. This contribution presents our own results, which support the hypothesis that these antigens might play a role in future cancer treatment. Material and methods: Fifty primary oral squamous cell carcinomas were stained immunohistochemically with the monoclonal antibody 57B. Twenty specimens (each) of epulis, ulcus, lichen planus, leukoplakia, follicular cysts and carcinoma in situ were stained immunohistochemically with the monoclonal antibody 57B. Five own cell lines of oral squamous cell carcinoma were characterized with quantitative real time PCR for their expression profile of MAGE-A2, -A3, -A4 and -A6. These cell lines were treated with taxanes (docetaxel, paclitaxel) in increasing doses. The count of viable cells after 24 h and 48 h was measured spectroscopically. Results: MAGE-A antigens were solely expressed in malignant tissues. No precancerous lesion examined expressed MAGE-A antigens. About 30% of dysplasia and 60% of oral squamous cell carcinoma expressed MAGE-A antigens. There was a correlation of
71
tumor size (T) and even more with the grading (G) and amount of MAGE-A expression. Other markers such as N, M, L, and V had no significant correlation with the MAGE-A expression. The cell lines examined expressed groups of MAGE-A antigen subspecialities. Mostly three antigens were expressed at the same time. One cell line responded significantly more weakly to treatment with taxanes. This cell line was the only one that expressed MAGE-A4. Conclusions: MAGE-A4 are solely expressed in malignant tissue and might be used as a tumor marker. They are expressed more often in more dysplastic tumors and therefore might indicate a poorer prognosis. The expression of MAGE-A4 alters the response rate to taxanes and has therefore implications for treatment. doi:10.1016/j.oos.2009.06.129
O45. Biomarkers of recurrence in oral carcinoma P. Reis a,*, M. Tomenson a,b, N. Cervigne a, M. Sukhai a, N. Naranjo Galloni c, L. Waldron d,e,f,g a
Ontario Cancer Institute, University Health Network, Canada University of Toronto, Canada c Calderon Guardia Hospital, Costa Rica d University Health Network, Canada e Toronto General Hospital, Canada f Princess Margaret Hospital, Canada g Princess Margaret Hospital, Canada b
Background: In Oral Squamous Cell Carcinoma (OSCC), local recurrence is a major cause of treatment failure and patient death and may be the result of residual tumor cells undetectable by histology or underlying genetic changes that prime tissues for malignant transformation. Molecular analysis of histologically normal (negative) surgical resection margins and OSCC may aid in identifying genetic targets involved in tumorigenesis and disease recurrence. Patient samples and methods: We performed oligonucleotide array analysis (Affymetrix) of 103 samples (margins, tumor and normal tissues) from 25 patients. Bioinformatics analysis of microarray data was performed using k-means clustering, I2D and GeneCODIS tools for pathway analysis. Validation of gene and protein expression was performed using quantitative real-time RT-PCR (QRT-PCR) and Immunohistochemistry (IHC). Results: We identified a commonly deregulated gene expression signature in margins and OSCCs. Interaction network analyses showed that genes involved in mitogenic signaling were significantly over-represented within this signature set. A subset of 12 genes (including EGFR and eIF4 genes) was validated by QRT-PCR in a larger cohort of 300 samples (margins, tumor and normal) from 40 OSCC patients. Seven of these genes, mainly involved in cell proliferation and invasion, were significantly deregulated genes in a subset of negative margins and their corresponding OSCCs. IHC analysis in a third independent cohort of patients with known outcome (recurrence vs. no recurrence) showed aberrant protein expression, including P53, C-Jun and eukaryotic initiation factor proteins. We are currently assessing whether mRNA and protein expression levels are correlated with tumor recurrence; this analysis will allow us to identify which gene subset has a predictive power for recurrence in OSCC patients. Conclusion: A commonly deregulated gene signature in negative margins and OSCC may be used, in combination with histology, for a better assessment of surgical margins in OSCC, ultimately leading to improved patient outcome. doi:10.1016/j.oos.2009.06.130
Oral AbstractsPoster ListOrals ListPan. Disc. & Symp. Abs.Keynote Abs.Keynote Bios.ProgramIAOOWelcomeCommittee Listings
Oral abstracts / Oral Oncology Supplement 3 (2009) 56–122
70
Oral abstracts / Oral Oncology Supplement 3 (2009) 56–122
identify molecular markers predicting the clinical behaviour of OSCC and SGT. In particular, the project attempts to disclose prognostic markers capable of defining the clinical course of three discrete classes of patients: those with early stage T1–T2 OSCC with unexpected aggressive behaviour; young patients (<40 years) affected by OSCC and lacking overt risk factors; and patients affected by metastatic SGT. Methods: In selected primary and metastatic lesions of OSCC we examined, at both mRNA and protein levels, the expression pattern of an apparently OSCC-enriched p63 variant and the 12 currently known cell surface-associated proteoglycans (NG2, syndecans-1-4 and glypicans-1-6). We evaluated these previously identified putative biomarkers both qualitatively and quantitatively and correlate their expression patterns with the clinical course of the patients. In parallel, we performed whole-genome comparative genetic screenings on primary lesions from metastatic and non-metastatic patients and secondary lesions of post-surgical patients. Both intact tumour samples and laser microdissected specimens were examined. These experimental approaches have been combined with hierarchical agglomerative clustering of previously identified gene markers through current bioinformatic algorithms and dedicated software tools. Expected results: We expect to reveal novel prognostic markers capable of predicting the unfavourable clinical course of early stage (T1–T2) OSCC patients, young (<40 years) OSCC patients lacking risk factors and individuals developing SGT. These molecular tools are instrumental for the clinical management and design of more tailored and individualized post-surgical treatments of subjects affected by these tumours. doi:10.1016/j.oos.2009.06.125
O41. Can SLUG, SNAI1, TWIST1, TGFß, N-cadherin and E-cadherin predict the metastatic potential of oral squamous cell carcinoma? E. Barker a,b, P. Reis b,*, M. Sukhai b, R. Goswami b, J. Irish a, S. Kamel-Reid b a b
Princess Margaret Hospital, Toronto, Canada The Ontario Cancer Institute, The University of Toronto, Canada
Introduction: Metastasis is a complex, multi-step process allowing primary tumours to spread to both regional and distant sites. Oral squamous cell carcinoma (OSCC) has significant potential for regional metastatic spread. The treatment of clinically node negative (cN0) necks remains controversial. A diagnostic test that could accurately predict the metastatic potential of OSCC would help define the appropriate treatment option for individual tumours. TWIST1, SNAI1 and SLUG are transcription factors that have shown to be dysregulated in aggressive human tumours. TGF-b is a growth factor also associated with poor clinical outcome. Both N-cadherin and E-cadherin are central in epithelial-mesenchymal transition. We hypothesised that SLUG, SNAI1, TWIST1, TGF-b, N-cadherin and E-cadherin could be used in combination to predict the metastatic potential of OSCC. Method: Fresh OSCC tumour samples [total = 48 patients; n = 24 N0; n = 24 (node positive) N+; n = 26 tongue; n = 17 floor of mouth (FOM); n = 5 other sites] and corresponding adjacent normal tissues (n = 21) were used for gene expression and protein analysis. Quantitative real-time RT-PCR was undertaken, TWIST1, SLUG, SNAI1, TGF-b, N-cadherin and E-cadherin expression quantified, using the Delta Delta Ct method, and correlated with protein expression as well as clinical and pathological parameters. Results: All genes were significantly differentially expressed, between adjacent normal tissue and the primary malignancy, independent of node status or primary site. When anatomical sites
were grouped, gene expression levels were significantly different for TWIST1 between N0 and N+ patients. When the ‘tongue’ sub site was analysed separately, both TWIST1 and SNAI1 had significantly reduced expression levels in the N+ patients compared with N0 patients. Protein levels are currently being analysed and will be correlated with expression data and presented. Conclusion: A combination of genes offers a potential genetic signature to predict the clinical course of OSCC. doi:10.1016/j.oos.2009.06.126
O42. Mcl-1 expression is associated with pathogenesis and radiotherapy treatment response in chewing tobacco-associated oral carcinomas T.R. Teni a,*, S. Mallick a, V. Palve a, S. Pawar a, R. Patil c, J.P. Agarwal b a
Advanced Centre for Treatment, Research and Education in Cancer (ACTREC) Kharghar, Navi Mumbai-410210, India b Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai 4000 12, India c Sharad Pawar Dental College, Wardha, India Expression of Bcl-2 family proteins in tumours can modulate apoptosis, influencing tumour behaviour and treatment. To investigate their role in oral tumorigenesis, nine Bcl-2 family transcripts were examined in three oral cell lines and 25 oral tumours using a Ribonuclease Protection Assay. Mcl-1 splice variants were assessed by RT-PCR and Mcl-1 protein was studied in normal, premalignant and malignant oral tissues and cell lines by immunohistochemistry and/or immunoblotting. A further 39 oral tumours prior to primary radiotherapy were assessed for expression of a set of proteins – Mcl-1, bclxl, p53, survivin and PCNA. The cell lines exhibited significantly higher levels of 7/9 Bcl-2 family transcripts as compared with those in normal tongue, and significantly higher (p = 0.030, p = 0.004) anti-apoptotic versus pro-apoptotic transcripts. Elevated Mcl-1 mRNA was observed in 11/25 (44%) tumours as compared with normal tissues with a five to tenfold higher expression of full length anti-apoptotic Mcl-1 transcript versus the pro-apoptotic short isoform. Strong cytoplasmic Mcl-1 immunoreactivity was detected predominantly in differentiated epithelia in 27/33 (82%) oral tumours, 18/20 (90%) leukoplakia, 25/30 (83%) submucous fibrosis, 3/3 oral cell lines, with weak staining in 8/15 (53%) normal mucosa samples. Mcl-1 positivity in malignant and premalignant tissues was comparable but significantly higher (p < 0.01) than that in normal mucosa. High expression of PCNA and Mcl-1 in oral tumours correlated significantly (p = 0.007), (p = 0.05) with poor disease free survival as compared with low expression respectively and were independent prognostic factors for predicting DFS. Our studies thus suggest an important role for Mcl-1 early in oral cancer pathogenesis in protecting cells from apoptosis via neutralization of pro-apoptotic members and could be a potential therapeutic target for oral cancers. Analysis of PCNA and Mcl-1 levels may be useful in predicting the clinical response in oral cancer patients receiving primary radiotherapy. doi:10.1016/j.oos.2009.06.127
O43. Induction of apoptosis in laryngeal cancer cells by a compound isolated from Pteris semipinnata L. G.G. Chen *, C.S. Lo, H.C. Liu, A.C. Vlantis, M.C.T. Tone, C.A. van Hasselt The Chinese University of Hong Kong, Hong Kong
Purpose: Apoptosis has been involved in the killing mechanism of a number of anti-cancer agents. Although the efficiency of chemotherapy for laryngeal cancer has been improved recently, we still lack an effective therapeutic protocol to improve the life quality of patients. In search of novel therapeutic agents, we have identified a compound (5F) from herb medicine, Pteris semipinnata L., which possesses a strong ability to induce apoptosis of tumor cells. Methods: Laryngeal cancer cells with or without human papillomavirus 16 (HPV16) or 18 (HPV18) were treated with 5F for 24–72 h. At the end of treatment, cell proliferation and apoptosis were measured. A number of apoptotic molecules were explored to identify the target molecules. Results: 5F markedly reduced the proliferation of tumor cells treated by 7F. A significant number of cells were found to be apoptotic. It was noted that the percentage of reduced proliferation did not correlate with apoptosis, suggesting that cell death may be involved in other death models. Nevertheless, apoptosis appears to be a major target in the 5F-mediated cell death pathway. We also found that laryngeal cancer with HPV infection was less sensitive to 5F treatment, indicating that HPV may protect tumor cells from apoptosis. Such a protective effect of HPV was removed when the nuclear factor kappaB was inhibited, suggesting that a positive relationship between HPV infection and the activity of nuclear factor kappaB. The findings also lead to a concept that the inhibitors of nuclear factor kappa B would enhance the anti-tumor effect of 5F in laryngeal cancer. Conclusions: 5F is an effective agent to induce apoptosis of laryngeal cancer and the killing effect can be enhanced when the activity of nuclear factor kappa B is inhibited. doi:10.1016/j.oos.2009.06.128
O44. MAGE-A antigens in oral squamous cell carcinoma U.D.A. Müller-Richter a,*, T. Reuther a, S. Rauthe b, S. Gattenlöhner b, A.C. Kübler a a Department of Oral and Maxillofacial Plastic Surgery, Universityhospital Würzburg, Germany b Institute of Pathology, Universityhospital Würzburg, Germany
Background: Oral squamous cell carcinoma is amongst the most common malignancies. Despite all the efforts of the last decades prognosis is still unfavourable. To improve treatment options and prognosis further characterization of this malignancy is mandatory. MAGE-A antigens, a subgroup of cancer/testis antigens, are exclusively expressed on malignant transformed cells. Their role and their importance in oral squamous cell carcinoma have to be explored as they might be used as tumor markers or targets in immunotherapy. This contribution presents our own results, which support the hypothesis that these antigens might play a role in future cancer treatment. Material and methods: Fifty primary oral squamous cell carcinomas were stained immunohistochemically with the monoclonal antibody 57B. Twenty specimens (each) of epulis, ulcus, lichen planus, leukoplakia, follicular cysts and carcinoma in situ were stained immunohistochemically with the monoclonal antibody 57B. Five own cell lines of oral squamous cell carcinoma were characterized with quantitative real time PCR for their expression profile of MAGE-A2, -A3, -A4 and -A6. These cell lines were treated with taxanes (docetaxel, paclitaxel) in increasing doses. The count of viable cells after 24 h and 48 h was measured spectroscopically. Results: MAGE-A antigens were solely expressed in malignant tissues. No precancerous lesion examined expressed MAGE-A antigens. About 30% of dysplasia and 60% of oral squamous cell carcinoma expressed MAGE-A antigens. There was a correlation of
71
tumor size (T) and even more with the grading (G) and amount of MAGE-A expression. Other markers such as N, M, L, and V had no significant correlation with the MAGE-A expression. The cell lines examined expressed groups of MAGE-A antigen subspecialities. Mostly three antigens were expressed at the same time. One cell line responded significantly more weakly to treatment with taxanes. This cell line was the only one that expressed MAGE-A4. Conclusions: MAGE-A4 are solely expressed in malignant tissue and might be used as a tumor marker. They are expressed more often in more dysplastic tumors and therefore might indicate a poorer prognosis. The expression of MAGE-A4 alters the response rate to taxanes and has therefore implications for treatment. doi:10.1016/j.oos.2009.06.129
O45. Biomarkers of recurrence in oral carcinoma P. Reis a,*, M. Tomenson a,b, N. Cervigne a, M. Sukhai a, N. Naranjo Galloni c, L. Waldron d,e,f,g a
Ontario Cancer Institute, University Health Network, Canada University of Toronto, Canada c Calderon Guardia Hospital, Costa Rica d University Health Network, Canada e Toronto General Hospital, Canada f Princess Margaret Hospital, Canada g Princess Margaret Hospital, Canada b
Background: In Oral Squamous Cell Carcinoma (OSCC), local recurrence is a major cause of treatment failure and patient death and may be the result of residual tumor cells undetectable by histology or underlying genetic changes that prime tissues for malignant transformation. Molecular analysis of histologically normal (negative) surgical resection margins and OSCC may aid in identifying genetic targets involved in tumorigenesis and disease recurrence. Patient samples and methods: We performed oligonucleotide array analysis (Affymetrix) of 103 samples (margins, tumor and normal tissues) from 25 patients. Bioinformatics analysis of microarray data was performed using k-means clustering, I2D and GeneCODIS tools for pathway analysis. Validation of gene and protein expression was performed using quantitative real-time RT-PCR (QRT-PCR) and Immunohistochemistry (IHC). Results: We identified a commonly deregulated gene expression signature in margins and OSCCs. Interaction network analyses showed that genes involved in mitogenic signaling were significantly over-represented within this signature set. A subset of 12 genes (including EGFR and eIF4 genes) was validated by QRT-PCR in a larger cohort of 300 samples (margins, tumor and normal) from 40 OSCC patients. Seven of these genes, mainly involved in cell proliferation and invasion, were significantly deregulated genes in a subset of negative margins and their corresponding OSCCs. IHC analysis in a third independent cohort of patients with known outcome (recurrence vs. no recurrence) showed aberrant protein expression, including P53, C-Jun and eukaryotic initiation factor proteins. We are currently assessing whether mRNA and protein expression levels are correlated with tumor recurrence; this analysis will allow us to identify which gene subset has a predictive power for recurrence in OSCC patients. Conclusion: A commonly deregulated gene signature in negative margins and OSCC may be used, in combination with histology, for a better assessment of surgical margins in OSCC, ultimately leading to improved patient outcome. doi:10.1016/j.oos.2009.06.130
Oral AbstractsPoster ListOrals ListPan. Disc. & Symp. Abs.Keynote Abs.Keynote Bios.ProgramIAOOWelcomeCommittee Listings
Oral abstracts / Oral Oncology Supplement 3 (2009) 56–122