- Email: [email protected]
MGMT Hypermethylation—Missing Piece of the Puzzle in Primary Head and Neck Squamous Cell Carcinoma?
Volume 94 Number 4 2016
Posters
276 XPAeA Biomarker With Potential Prognostic Value in Patients With Oropharyngeal Head and Neck Squamous Cell Carcinoma S. Prochnow, A. Muenscher, R. Knecht, W. Wilczak, and T. Clauditz; University Hospital Hamburg-Eppendorf, Hamburg, Germany Purpose/Objective(s): Platinum-based chemotherapy resistance has been under investigation for a long time, looking at the nucleotide excision repair (NER) pathway, which is responsible for DNA adduct repair. One of the participating proteins in that pathway is XPA. There is little information about this protein regarding its prognostic value in patients with head and neck squamous cell carcinoma (HNSCC). Therefore, we investigated XPA expression as a prognostic factor by retrospectively looking at overall survival, time to recurrence, and correlation with clinical parameters. Materials/Methods: Tissue microarrays were constructed from 453 cases of HNSCC including 222 oral (49%), 126 pharyngeal (27.8%), and 105 laryngeal (23.2%) tumors. Two hundred ninety-three tumor blocks were evaluable for XPA immunohistochemistry. Expression levels were dichotomized into a high and low XPA expressing group followed by a comparison of age, gender, TNM status, grading, and UICC stage. Outcomes for overall survival and time to recurrence were analyzed by using the Kaplan-Meier method and performed for different subsites of the head and neck. Results: Analysis of overall survival and time to recurrence showed no difference between both expression levels of XPA in the overall patient cohort. However, superior overall survival in patients with oropharyngeal SCC and a high XPA expression could be observed (PZ.0386). Looking at SCCs of the oral cavity, a trend toward an inferior overall survival in patients with a high XPA expression was seen, whereas investigations in the hypopharynx and larynx showed no significant differences between high and low XPA expressing tumors. Looking generally at gender, M stage, and grading, no statistical correlation was found. Analyzing T and N stage in all tumors, a trend toward a lower XPA expression in advanced tumors (>pT4 PZ.0543 and >pN1 PZ.0546) could be seen. This trend was confirmed by statistical lower expression of XPA in patients with UICC stage IV looking at the overall patient cohort (PZ.035). Conclusion: The shown results suggest that XPA might be a novel predictive marker for overall survival in patients with oropharyngeal SCC with a superior survival in tumors with a high XPA expression. Furthermore, this study shows that subsites in the head and neck will have to be looked at separately in the future to determine the predictive value of biomarkers for therapy outcome and pretherapeutic risk stratification of patients. To increase statistical power of this study and to evaluate the effect on platinum-based chemotherapy resistance, further studies with even larger patient cohorts will be needed and are ongoing. Author Disclosure: S. Prochnow: None. A. Muenscher: None. R. Knecht: Advisory Board of Merck; Advisory Board of Merck. W. Wilczak: None. T. Clauditz: None.
277 MGMT HypermethylationdMissing Piece of the Puzzle in Primary Head and Neck Squamous Cell Carcinoma? S.G. Jhavar, D. Fink, A. Rao, and N. Deb; Baylor Scott & White Healthcare Temple Clinic, Temple, TX
939
Purpose/Objective(s): A secific mechanism explaining the higher chemoradiation responsiveness of human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) and the modulation of this effect by tobacco exposure remains unidentified. Promoter hypermethylation (HM) of the DNA-repair O6-Methylguanine (O6-MG)-DNAmethyl-transferase (MGMT) gene is an independent predictor of response to chemoradiation and survival in gliomas and lymphomas. We are investigating the role of MGMT in HNSCC in the context of tobacco exposure and HPV status. Materials/Methods: After exclusion of patients with no pathology, cytology only, and outside slides, primary HNSCC patients suitable for this ongoing investigation were identified from the institutional cancer database after we secured institutional review board approval. Tumor was extracted from paraffin blocks using laser-capture microdissection. DNA was extracted from the tumor followed by bisulphite treatment, methylation-specific PCR, and pyrosequencing using a commercially available kit. In addition, HPV status was ascertained with the help of p16 immunohistochemistry. Age, gender, site, stage, and tobacco use was extracted from patient charts. Results: As a part of this ongoing investigation, we provide the interim report on 100 cases with both MGMT and p16 status. MGMT-HM was seen in 35% of patients (35 of 100). The distribution of HNSCC tumors with respect to HPV status, tobacco use, and MGMT-HM is shown in Table 1. Tobacco status did not influence HPV status (45% [33 of 73] of tobaccoassociated cancers vs 56% [15 of 27] of tobacco-unassociated cancers were p16 positive; PZ.3; Fisher exact test). HPV status did not influence MGMT status (35% [17 of 48] p16 positive cancers vs 35% [18 of 52] p16 negative cancers had MGMT-HM; PZ1.0; Fisher exact test). However, tobacco use was found to be significantly associated with MGMT status (29% [21 of 73] tobacco-associated cancers vs 52% [14 of 27] tobaccounassociated cancers had MGMT-HM; PZ.0369; Fisher exact test). Furthermore, tobacco use influenced MGMT status particularly in the HPV-positive subgroup (27% [9 of 33] tobacco-associated/p16-positive cancers vs 53% [8 of 15] tobacco-unassociated/p16-positive cancers had MGMT-HM; PZ.04; X2 test). Conclusion: At least one-third of HNSCC patients have MGMT-HM. To our knowledge, this is first study to report an association between tobacco use and MGMT status, especially in HPV-positive HNSCC. Author Disclosure: S.G. Jhavar: None. D. Fink: None. A. Rao: None. N. Deb: None.
278 Variations in Genome Structure Between Follicular Variant and Highly Aggressive Papillary Thyroid Cancer D.V. Bann,1 K.E. Sheldon,2 K. Houser,2 L. Zhang,2 J. Broach,2 and D. Goldenberg1; 1Penn State Milton S. Hershey Medical Center, Hershey, PA, 2Penn State College of Medicine, Hershey, PA Purpose/Objective(s): Structural genome instability is a cardinal feature of cancer. Genomic structural variations (SVs), including insertions, deletions, inversions, copy number alterations, and translocations, acquired during malignant transformation may alter gene expression, resulting in tumor growth, invasion, and metastasis. However, the short reads of 50-200 base pairs (bp) used by many next-generation sequencing technologies lead to systematic errors in identifying and localizing SVs within the genome. To understand how SVs contribute to invasion or metastasis we
Abstract 277; Table 1 HPV+ (nZ48) Tobacco+ (nZ33)
HPV- (nZ52) Tobaccoe (nZ15)
Tobacco+ (nZ40)
Tobaccoe (nZ12)
MGMT -HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
9 (27%)
24 (73%)
8 (53%)
7 (47%)
12 (30%)
28 (70%)
6 (50%)
6 (50%)
Posters
276 XPAeA Biomarker With Potential Prognostic Value in Patients With Oropharyngeal Head and Neck Squamous Cell Carcinoma S. Prochnow, A. Muenscher, R. Knecht, W. Wilczak, and T. Clauditz; University Hospital Hamburg-Eppendorf, Hamburg, Germany Purpose/Objective(s): Platinum-based chemotherapy resistance has been under investigation for a long time, looking at the nucleotide excision repair (NER) pathway, which is responsible for DNA adduct repair. One of the participating proteins in that pathway is XPA. There is little information about this protein regarding its prognostic value in patients with head and neck squamous cell carcinoma (HNSCC). Therefore, we investigated XPA expression as a prognostic factor by retrospectively looking at overall survival, time to recurrence, and correlation with clinical parameters. Materials/Methods: Tissue microarrays were constructed from 453 cases of HNSCC including 222 oral (49%), 126 pharyngeal (27.8%), and 105 laryngeal (23.2%) tumors. Two hundred ninety-three tumor blocks were evaluable for XPA immunohistochemistry. Expression levels were dichotomized into a high and low XPA expressing group followed by a comparison of age, gender, TNM status, grading, and UICC stage. Outcomes for overall survival and time to recurrence were analyzed by using the Kaplan-Meier method and performed for different subsites of the head and neck. Results: Analysis of overall survival and time to recurrence showed no difference between both expression levels of XPA in the overall patient cohort. However, superior overall survival in patients with oropharyngeal SCC and a high XPA expression could be observed (PZ.0386). Looking at SCCs of the oral cavity, a trend toward an inferior overall survival in patients with a high XPA expression was seen, whereas investigations in the hypopharynx and larynx showed no significant differences between high and low XPA expressing tumors. Looking generally at gender, M stage, and grading, no statistical correlation was found. Analyzing T and N stage in all tumors, a trend toward a lower XPA expression in advanced tumors (>pT4 PZ.0543 and >pN1 PZ.0546) could be seen. This trend was confirmed by statistical lower expression of XPA in patients with UICC stage IV looking at the overall patient cohort (PZ.035). Conclusion: The shown results suggest that XPA might be a novel predictive marker for overall survival in patients with oropharyngeal SCC with a superior survival in tumors with a high XPA expression. Furthermore, this study shows that subsites in the head and neck will have to be looked at separately in the future to determine the predictive value of biomarkers for therapy outcome and pretherapeutic risk stratification of patients. To increase statistical power of this study and to evaluate the effect on platinum-based chemotherapy resistance, further studies with even larger patient cohorts will be needed and are ongoing. Author Disclosure: S. Prochnow: None. A. Muenscher: None. R. Knecht: Advisory Board of Merck; Advisory Board of Merck. W. Wilczak: None. T. Clauditz: None.
277 MGMT HypermethylationdMissing Piece of the Puzzle in Primary Head and Neck Squamous Cell Carcinoma? S.G. Jhavar, D. Fink, A. Rao, and N. Deb; Baylor Scott & White Healthcare Temple Clinic, Temple, TX
939
Purpose/Objective(s): A secific mechanism explaining the higher chemoradiation responsiveness of human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) and the modulation of this effect by tobacco exposure remains unidentified. Promoter hypermethylation (HM) of the DNA-repair O6-Methylguanine (O6-MG)-DNAmethyl-transferase (MGMT) gene is an independent predictor of response to chemoradiation and survival in gliomas and lymphomas. We are investigating the role of MGMT in HNSCC in the context of tobacco exposure and HPV status. Materials/Methods: After exclusion of patients with no pathology, cytology only, and outside slides, primary HNSCC patients suitable for this ongoing investigation were identified from the institutional cancer database after we secured institutional review board approval. Tumor was extracted from paraffin blocks using laser-capture microdissection. DNA was extracted from the tumor followed by bisulphite treatment, methylation-specific PCR, and pyrosequencing using a commercially available kit. In addition, HPV status was ascertained with the help of p16 immunohistochemistry. Age, gender, site, stage, and tobacco use was extracted from patient charts. Results: As a part of this ongoing investigation, we provide the interim report on 100 cases with both MGMT and p16 status. MGMT-HM was seen in 35% of patients (35 of 100). The distribution of HNSCC tumors with respect to HPV status, tobacco use, and MGMT-HM is shown in Table 1. Tobacco status did not influence HPV status (45% [33 of 73] of tobaccoassociated cancers vs 56% [15 of 27] of tobacco-unassociated cancers were p16 positive; PZ.3; Fisher exact test). HPV status did not influence MGMT status (35% [17 of 48] p16 positive cancers vs 35% [18 of 52] p16 negative cancers had MGMT-HM; PZ1.0; Fisher exact test). However, tobacco use was found to be significantly associated with MGMT status (29% [21 of 73] tobacco-associated cancers vs 52% [14 of 27] tobaccounassociated cancers had MGMT-HM; PZ.0369; Fisher exact test). Furthermore, tobacco use influenced MGMT status particularly in the HPV-positive subgroup (27% [9 of 33] tobacco-associated/p16-positive cancers vs 53% [8 of 15] tobacco-unassociated/p16-positive cancers had MGMT-HM; PZ.04; X2 test). Conclusion: At least one-third of HNSCC patients have MGMT-HM. To our knowledge, this is first study to report an association between tobacco use and MGMT status, especially in HPV-positive HNSCC. Author Disclosure: S.G. Jhavar: None. D. Fink: None. A. Rao: None. N. Deb: None.
278 Variations in Genome Structure Between Follicular Variant and Highly Aggressive Papillary Thyroid Cancer D.V. Bann,1 K.E. Sheldon,2 K. Houser,2 L. Zhang,2 J. Broach,2 and D. Goldenberg1; 1Penn State Milton S. Hershey Medical Center, Hershey, PA, 2Penn State College of Medicine, Hershey, PA Purpose/Objective(s): Structural genome instability is a cardinal feature of cancer. Genomic structural variations (SVs), including insertions, deletions, inversions, copy number alterations, and translocations, acquired during malignant transformation may alter gene expression, resulting in tumor growth, invasion, and metastasis. However, the short reads of 50-200 base pairs (bp) used by many next-generation sequencing technologies lead to systematic errors in identifying and localizing SVs within the genome. To understand how SVs contribute to invasion or metastasis we
Abstract 277; Table 1 HPV+ (nZ48) Tobacco+ (nZ33)
HPV- (nZ52) Tobaccoe (nZ15)
Tobacco+ (nZ40)
Tobaccoe (nZ12)
MGMT -HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
MGMT-HM
MGMT unmethylated
9 (27%)
24 (73%)
8 (53%)
7 (47%)
12 (30%)
28 (70%)
6 (50%)
6 (50%)