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EXPRESSION OF DENDRITIC, LANGERHANS AND T CELLS IN POTENTIALLY MALIGNANT LESIONS AND ORAL SQUAMOUS CELL CARCINOMA
ORAL AND MAXILLOFACIAL PATHOLOGY e138 Abstracts RP70 - ORAL HEALTH EVALUATION IN ELDERLY ALZHEIMER PATIENTS. MARIANA ISRAEL ROCHA, ANDRÉA LOPEZ SOTO, MICHELLE DANIELLE MATIAS, RAQUEL CONCEIÇÃO FERREIRA, MARCO TÚLIO GUALBERTO CINTRA, MARIA CÁSSIA FERREIRA DE AGUIAR. This cross sectional study aimed to describe the profile of elderly patients with Alzheimer disease in early stages and their oral health status. Study Design: 35 participants were evaluated with Minimental state (MEEM), 10-meter walking test and classified according to the Clinical Dementia Rating (CDR). Were included only patients CDR1 and CDR2. The oral health evaluation considered the use of removable prosthesis, presence of oral lesions and patient’s hygiene. Additionally, comorbidities, use of medicine, tobacco and alcohol were also registered. Results: There were 21 female and 14 male patients (mean age 76.1 years). The scores of MEEM ranged between 10 and 23 points; the mean value of 10-meter walking test was 0.57 m/s. The most frequent comorbidity was arterial hypertension and 28.5% of elderly used more than 7 drugs per day. Alcohol and tobacco intake was reported for 6 and 5 participants, respectively. The majority of the elderly (71.4%) wore a removable prosthesis, most of them in poor conditions and with deficient hygiene. Chronic erythematous candidiasis (5), Fordyce’s granules (5) and varicosities (5) were the most common alterations. Conclusion: The oral health status of elderly Alzheimer patients deserves attention and must be considered for the global planning treatment. Support: CNPq #309322/2015-4 - FAPEMIG.
RP71 - IMPLANT AND PROSTHESIS SURVIVAL RATES OF EXTRAORAL IMPLANTS IN THE REHABILITATION OF ORBITAL DEFECTS. PATRICIA MARTINS BUENO, THALITA CAMPOS NUNES, ANTHONY BENITES CONDEZO, RAFAEL ZETEHAKU ARAUJO, CAMILA LOPES CARDOSO, MARCELO FERRAZ OLIVEIRA, MARCOS MARTINS CURI. The objective of this study was to evaluate implant and prosthesis survival rates and the soft tissue reactions around the extraoral implants used to support orbital defects. Study Design: A retrospective study was performed of patients who received implants for craniofacial rehabilitation from 2003 to 2015. Two outcome variables were considered: implant and prosthetic success. A statistical model was used to estimate survival rates and associated confidence intervals. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. Results: A total of 33 titanium implants were placed in 14 patients. The 2-year overall implant survival rates were 100% and the 2-year overall prosthesis survival rates were 92.3%. Conclusion: From this study, it was concluded that craniofacial rehabilitation with extraoral implants is a safe, reliable and predictable method to restore the patient’s normal appearance.
RP72 - ASSOCIATION OF CHEMOKINE RECEPTORS AND LIGANDS WITH PATHOLOGIC INDICATORS AND SURVIVAL RATE IN SQUAMOUS CELL CARCINOMA. ANTONIO ERNANDO CARLOS FERREIRA JUNIOR, CAMILA CARVALHO DE OLIVEIRA, KARUZA MARIA ALVES PEREIRA, MARIA DO PERPÉTUO SOCORRO SALDANHA DA CUNHA,
OOOO August 2017 FABRÍCIO BITU SOUSA, MÁRIO ROGÉRIO LIMA MOTA, ANA PAULA NEGREIROS NUNES ALVES. To evaluate the expression of CXCR4, CXCL12, CCR7, CCL21 and Ki-67 in oral squamous cell carcinoma and correlate these markers with lymph node metastasis and survival rates. Study Design: Data about the anatomic location of the lesion, gender, age, survival, presence or absence of lymph node metastasis, lymph-vascular invasion and invasion depth was collected. The expression of the chemokines and their respective receptors was performed by immunohistochemistry (technical streptavidin-biotin-peroxidase). Results: The expression of CXCR4, CXCL12, CCR7 and CCL21 was observed in 18 (60%), 8 (22.66%), 16 (53.3%) and 3 (12 %) cases, respectively. It was found a significant association between lymph-vascular invasion and immunostaining of CXCR4 (P ¼ .007) and CCR7 (P ¼ .01), furthermore, metastasis was present in 62.5% and 37.5% among this cases, respectively. A significant positive correlation was found between Ki-67 and CXCR4 (P ¼ .0086), CXCL12 (P ¼ .036) and CCR7 (P ¼ .04). After 111 months, only 38.4% of CXCR4+ patients were alive, while for CCR7+ after 62 months all had already died. Conclusion: These chemokines are associated with lymph-vascular invasion and cell proliferation perhaps favoring the development of metastases and poor prognosis.
RP73 - PREVALENCE OF INFECTIOUS ORAL LESIONS IN A REFERRAL CENTER. TARSILA DE CARVALHO FREITAS RAMOS, RAFAEL CABRAL DE ALBUQUERQUE SOUZA, LORENA ARAUJO ALMEIDA, GABRIEL LEVI DA SILVA CUNHA, LAYSE ROCHA BATISTA, JOANA DOURADO MARTINS, MÁRCIO CAMPOS OLIVEIRA. Epidemiologic studies of lesions involving the oral-maxillofacial complex are important for the dental surgeon since they demonstrate the prevalence and incidence of diseases. This crosssectional study evaluated records of 384 patients affected by infectious oral lesions and submitted to clinical or histopathologic examination between 1998 and 2015. The Statistical Package for Social Sciences was used for statistical analysis. Chi-square tests were used to test associations between variables, with the level of significance set .05. In relation to the classification of lesions, the fungal lesions were most prevalent (78%), followed by viral (11%) and bacterial lesions (9%). Among the patients, 76.8% were females, 61.7% were over 40 years of age, and 66.4% were non-white. The palate was the most affected site by the lesions (52%) and the prosthetic stomatitis and herpes simplex were the most prevalent (22% e 4.4%). A significant association was observed between the presence of fungal lesion and the variables age and gender of the patients, between denture use and prosthetic stomatitis. For viral lesions was a significant association between the presence of the lesion and the variables age and anatomic location. For bacterial lesions was a significant association for the variables age and gender.
RP74 - EXPRESSION OF DENDRITIC, LANGERHANS AND T CELLS IN POTENTIALLY MALIGNANT LESIONS AND ORAL SQUAMOUS CELL CARCINOMA. PABLO AGUSTIN VARGAS, ANA CAROLINA AMORIM PELLICIOLI, MANOELA DOMINGUES MARTINS, PAULA FARTHING, PAUL SPEIGHT, MÁRCIO AJUDARTE LOPES, LYNNE BINGLE.
OOOO Volume 124, Number 2 Oral squamous cell carcinomas (OSCC) may arise from potential malignant lesions, such as leukoplakia. The immune system plays an important role recognizing tumor precursor cells. However, because of the immunoediting mechanisms cancer cells are able to escape the immune system surveillance. Objective: Evaluate the profile of dendritic and T cells in epithelial dysplasia (ED), proliferative verrucous leukoplakia (PVL) and OSCC and correlate these findings with clinical data. Study Design: 50 cases of OSCC, 50 of ED and 15 of PVL were immunostained for CD1a, CD83, CD303 and CD8 followed by a quantitative analysis. Results: Analysis revealed significantly increased number of CD1a and CD83 in ED compared with PVL and SCC groups, respectively. CD303 was significantly increased in the OSCC group when compared with ED and PVL. CD8 counting was significantly higher in OSCC and ED when compared with PVL. Conclusion: The number of mature and immature dendritic cells (DC) was increased in ED, suggesting that the tumor cells may be evading the immune system. However, the number of plasmacytoid DC was higher in the OSCC group, suggesting that this marker might be associated with aggressive lesions. Key Words: immune system, dendritic cells, oral squamous cell carcinoma, leukoplakia, epithelial dysplasia, proliferative verrucous leukoplakia.
RP75 - IMMUNOEXPRESSION OF UPA AND UPAR IN ORAL TONGUE SQUAMOUS CELL CARCINOMA: ASSOCIATION WITH CLINICOPATHOLOGIC PARAMETERS. MARIANNA SAMPAIO SERPA, RODRIGO PORPINO MAFRA, SALOMÃO ISRAEL MONTEIRO LOURENÇO QUEIROZ, LEORIK PEREIRA DA SILVA, ANDRÉIA FERREIRA DO CARMO, LÉLIA BATISTA DE SOUZA, LEÃO PEREIRA PINTO. The aim of this study was to assess the immunoexpression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in 46 cases of oral tongue squamous cell carcinoma (OTSCC). The expression of these biomarkers was compared with clinicopathologic parameters. Immunostaining was evaluated semi-quantitatively in the invasive front and tumor core. Scores were assigned based on the proportion of positive cells: 0 (0%), 1 (1%-10%), 2 (11%-50%) and 3 (>50%). The immunoexpression of uPA was not associated with clinical parameters. Regarding the histologic grade of malignancy, a higher expression of uPA was observed in cases of high-grade malignancy (P¼.05) and worst mode of invasion (P¼.03). As for uPAR, it was observed a higher expression in cases with locoregional recurrence (P¼.04) and no significant differences were observed in relation to lymph node metastasis, clinical TNM staging, overall outcome, and histologic grade of malignancy. Overall, a higher expression of uPA and uPAR was observed at the invasive front of the tumor in relation to the tumor core (P<.001). These results suggest that uPA and uPAR are involved in the progression of OTSCC, participating mainly in the deepest region of the tumor.
RP76 - INTERROGATION OF CANCER HOTSPOT MUTATIONS IN CALCIFYING CYSTIC ODONTOGENIC TUMOR. SILVIA FERREIRA DE SOUSA, RENNAN GARCIA MOREIRA, RICARDO SANTIAGO GOMEZ, CAROLINA CAVALIÉRI GOMES.
ABSTRACTS Abstracts e139 To simultaneously interrogate in calcifying cystic odontogenic tumor (CCOT) about 2,800 COSMIC mutations in a panel of important oncogenes and tumor suppressor genes. Study Design: 3 samples of CCOT were analyzed. It was used the Ion AmpliSeq Cancer Hotspot Panel v2 to interrogate mutations at 50 tumor suppressor genes and oncogenes by target next generation sequencing on the Ion Personal Genome Machine (PGM) System. Reads were aligned to genome (hg19), variants were called using Ion Reporter Software and false variants were excluded after assessment at the Integrative Genomics Viewer (IGV). Results: The only pathogenic mutation detected in 2 out of 3 CCOT was in b-Catenin gene, CTNNB1 c.98C>T. This mutation leads to substitution from serine to phenylalanine at codon 33 of b-Catenin, resulting in its stabilization and oncogenic activation. No other pathogenic mutation interrogated was detected, including the recurrent mutations BRAFV600E, recently described in ameloblastomas or KRASG12V, recently described in adenomatoid odontogenic tumors. Conclusion: b-Catenin gene mutation persists as the pivotal alteration reported in CCOTs. This study gives further support to the concept that odontogenic tumors do not share a common genetic event and each tumor type shows a specific molecular profile. (CNPq # 165805/2015-3 and FAPEMIG).
RP77 - IN VIVO AND IN VITRO EFFECTS OF CURCUMIN ON HEAD AND NECK CARCINOMA: A SYSTEMATIC REVIEW. GABRIEL ÁLVARES BORGES, DANIELA FORTUNATO RÊGO, DANIELE XAVIER ASSAD, RICARDO DELLA COLETTA, GRAZIELA DE LUCA CANTO, ELIETE NEVES DA SILVA GUERRA. Head and neck squamous cell carcinoma (HNSCC) causes globally a high number of deaths. Therefore, more effective and less deleterious therapies are required. In this sense, the study of phytochemicals points to their use as chemo-preventive agents. All considered, the objective of this systematic review was to investigate the effects of curcumin on proliferation and survival of HNSCC. This study was based on the PRISMA Checklist. The search was conducted on 6 databases: Cochrane, LILACS, MEDLINE, PubMed, Web of Science and EMBASE. In vitro and in vivo studies that evaluated the effects of curcumin on cell viability, tumor growth, cell cycle or cell death in HNSCC cell lines or animal models were selected. Out of 387 gathered studies, 30 met the inclusion criteria. These studies demonstrated that curcumin induces cytotoxicity, intrinsic pathway apoptosis and G2/S-arrest in HSNCC cells. It also reduces tumor measurements in animal models. These events were mostly studied with MTT assay, flow cytometry and expression of cell cycle and apoptosis-related proteins. This systematic review demonstrated that curcumin has effect on HNSCC cell proliferation and survival, reinforcing the currently available evidence that it could be an effective adjuvant drug in HNSCC treatment.
RP78 - CLINICOPATHOLOGIC STUDY BETWEEN ORAL LEUKOPLAKIA AND PROLIFERATIVE VERRUCOUS LEUKOPLAKIA. DARCY FERNANDES, CLÁUDIA MARIA NAVARRO, MIRIAN APARECIDA ONOFRE, ELAINE MARIA SGAVIOLI MASSUCATO, ANDREIA BUFALINO. Proliferative verrucous leukoplakia (PVL) is a subtype of oral leukoplakia (OL), being characterized by multifocal presentation, resistance to treatment and a high rate of malignant transformation.
RP71 - IMPLANT AND PROSTHESIS SURVIVAL RATES OF EXTRAORAL IMPLANTS IN THE REHABILITATION OF ORBITAL DEFECTS. PATRICIA MARTINS BUENO, THALITA CAMPOS NUNES, ANTHONY BENITES CONDEZO, RAFAEL ZETEHAKU ARAUJO, CAMILA LOPES CARDOSO, MARCELO FERRAZ OLIVEIRA, MARCOS MARTINS CURI. The objective of this study was to evaluate implant and prosthesis survival rates and the soft tissue reactions around the extraoral implants used to support orbital defects. Study Design: A retrospective study was performed of patients who received implants for craniofacial rehabilitation from 2003 to 2015. Two outcome variables were considered: implant and prosthetic success. A statistical model was used to estimate survival rates and associated confidence intervals. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. Results: A total of 33 titanium implants were placed in 14 patients. The 2-year overall implant survival rates were 100% and the 2-year overall prosthesis survival rates were 92.3%. Conclusion: From this study, it was concluded that craniofacial rehabilitation with extraoral implants is a safe, reliable and predictable method to restore the patient’s normal appearance.
RP72 - ASSOCIATION OF CHEMOKINE RECEPTORS AND LIGANDS WITH PATHOLOGIC INDICATORS AND SURVIVAL RATE IN SQUAMOUS CELL CARCINOMA. ANTONIO ERNANDO CARLOS FERREIRA JUNIOR, CAMILA CARVALHO DE OLIVEIRA, KARUZA MARIA ALVES PEREIRA, MARIA DO PERPÉTUO SOCORRO SALDANHA DA CUNHA,
OOOO August 2017 FABRÍCIO BITU SOUSA, MÁRIO ROGÉRIO LIMA MOTA, ANA PAULA NEGREIROS NUNES ALVES. To evaluate the expression of CXCR4, CXCL12, CCR7, CCL21 and Ki-67 in oral squamous cell carcinoma and correlate these markers with lymph node metastasis and survival rates. Study Design: Data about the anatomic location of the lesion, gender, age, survival, presence or absence of lymph node metastasis, lymph-vascular invasion and invasion depth was collected. The expression of the chemokines and their respective receptors was performed by immunohistochemistry (technical streptavidin-biotin-peroxidase). Results: The expression of CXCR4, CXCL12, CCR7 and CCL21 was observed in 18 (60%), 8 (22.66%), 16 (53.3%) and 3 (12 %) cases, respectively. It was found a significant association between lymph-vascular invasion and immunostaining of CXCR4 (P ¼ .007) and CCR7 (P ¼ .01), furthermore, metastasis was present in 62.5% and 37.5% among this cases, respectively. A significant positive correlation was found between Ki-67 and CXCR4 (P ¼ .0086), CXCL12 (P ¼ .036) and CCR7 (P ¼ .04). After 111 months, only 38.4% of CXCR4+ patients were alive, while for CCR7+ after 62 months all had already died. Conclusion: These chemokines are associated with lymph-vascular invasion and cell proliferation perhaps favoring the development of metastases and poor prognosis.
RP73 - PREVALENCE OF INFECTIOUS ORAL LESIONS IN A REFERRAL CENTER. TARSILA DE CARVALHO FREITAS RAMOS, RAFAEL CABRAL DE ALBUQUERQUE SOUZA, LORENA ARAUJO ALMEIDA, GABRIEL LEVI DA SILVA CUNHA, LAYSE ROCHA BATISTA, JOANA DOURADO MARTINS, MÁRCIO CAMPOS OLIVEIRA. Epidemiologic studies of lesions involving the oral-maxillofacial complex are important for the dental surgeon since they demonstrate the prevalence and incidence of diseases. This crosssectional study evaluated records of 384 patients affected by infectious oral lesions and submitted to clinical or histopathologic examination between 1998 and 2015. The Statistical Package for Social Sciences was used for statistical analysis. Chi-square tests were used to test associations between variables, with the level of significance set .05. In relation to the classification of lesions, the fungal lesions were most prevalent (78%), followed by viral (11%) and bacterial lesions (9%). Among the patients, 76.8% were females, 61.7% were over 40 years of age, and 66.4% were non-white. The palate was the most affected site by the lesions (52%) and the prosthetic stomatitis and herpes simplex were the most prevalent (22% e 4.4%). A significant association was observed between the presence of fungal lesion and the variables age and gender of the patients, between denture use and prosthetic stomatitis. For viral lesions was a significant association between the presence of the lesion and the variables age and anatomic location. For bacterial lesions was a significant association for the variables age and gender.
RP74 - EXPRESSION OF DENDRITIC, LANGERHANS AND T CELLS IN POTENTIALLY MALIGNANT LESIONS AND ORAL SQUAMOUS CELL CARCINOMA. PABLO AGUSTIN VARGAS, ANA CAROLINA AMORIM PELLICIOLI, MANOELA DOMINGUES MARTINS, PAULA FARTHING, PAUL SPEIGHT, MÁRCIO AJUDARTE LOPES, LYNNE BINGLE.
OOOO Volume 124, Number 2 Oral squamous cell carcinomas (OSCC) may arise from potential malignant lesions, such as leukoplakia. The immune system plays an important role recognizing tumor precursor cells. However, because of the immunoediting mechanisms cancer cells are able to escape the immune system surveillance. Objective: Evaluate the profile of dendritic and T cells in epithelial dysplasia (ED), proliferative verrucous leukoplakia (PVL) and OSCC and correlate these findings with clinical data. Study Design: 50 cases of OSCC, 50 of ED and 15 of PVL were immunostained for CD1a, CD83, CD303 and CD8 followed by a quantitative analysis. Results: Analysis revealed significantly increased number of CD1a and CD83 in ED compared with PVL and SCC groups, respectively. CD303 was significantly increased in the OSCC group when compared with ED and PVL. CD8 counting was significantly higher in OSCC and ED when compared with PVL. Conclusion: The number of mature and immature dendritic cells (DC) was increased in ED, suggesting that the tumor cells may be evading the immune system. However, the number of plasmacytoid DC was higher in the OSCC group, suggesting that this marker might be associated with aggressive lesions. Key Words: immune system, dendritic cells, oral squamous cell carcinoma, leukoplakia, epithelial dysplasia, proliferative verrucous leukoplakia.
RP75 - IMMUNOEXPRESSION OF UPA AND UPAR IN ORAL TONGUE SQUAMOUS CELL CARCINOMA: ASSOCIATION WITH CLINICOPATHOLOGIC PARAMETERS. MARIANNA SAMPAIO SERPA, RODRIGO PORPINO MAFRA, SALOMÃO ISRAEL MONTEIRO LOURENÇO QUEIROZ, LEORIK PEREIRA DA SILVA, ANDRÉIA FERREIRA DO CARMO, LÉLIA BATISTA DE SOUZA, LEÃO PEREIRA PINTO. The aim of this study was to assess the immunoexpression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in 46 cases of oral tongue squamous cell carcinoma (OTSCC). The expression of these biomarkers was compared with clinicopathologic parameters. Immunostaining was evaluated semi-quantitatively in the invasive front and tumor core. Scores were assigned based on the proportion of positive cells: 0 (0%), 1 (1%-10%), 2 (11%-50%) and 3 (>50%). The immunoexpression of uPA was not associated with clinical parameters. Regarding the histologic grade of malignancy, a higher expression of uPA was observed in cases of high-grade malignancy (P¼.05) and worst mode of invasion (P¼.03). As for uPAR, it was observed a higher expression in cases with locoregional recurrence (P¼.04) and no significant differences were observed in relation to lymph node metastasis, clinical TNM staging, overall outcome, and histologic grade of malignancy. Overall, a higher expression of uPA and uPAR was observed at the invasive front of the tumor in relation to the tumor core (P<.001). These results suggest that uPA and uPAR are involved in the progression of OTSCC, participating mainly in the deepest region of the tumor.
RP76 - INTERROGATION OF CANCER HOTSPOT MUTATIONS IN CALCIFYING CYSTIC ODONTOGENIC TUMOR. SILVIA FERREIRA DE SOUSA, RENNAN GARCIA MOREIRA, RICARDO SANTIAGO GOMEZ, CAROLINA CAVALIÉRI GOMES.
ABSTRACTS Abstracts e139 To simultaneously interrogate in calcifying cystic odontogenic tumor (CCOT) about 2,800 COSMIC mutations in a panel of important oncogenes and tumor suppressor genes. Study Design: 3 samples of CCOT were analyzed. It was used the Ion AmpliSeq Cancer Hotspot Panel v2 to interrogate mutations at 50 tumor suppressor genes and oncogenes by target next generation sequencing on the Ion Personal Genome Machine (PGM) System. Reads were aligned to genome (hg19), variants were called using Ion Reporter Software and false variants were excluded after assessment at the Integrative Genomics Viewer (IGV). Results: The only pathogenic mutation detected in 2 out of 3 CCOT was in b-Catenin gene, CTNNB1 c.98C>T. This mutation leads to substitution from serine to phenylalanine at codon 33 of b-Catenin, resulting in its stabilization and oncogenic activation. No other pathogenic mutation interrogated was detected, including the recurrent mutations BRAFV600E, recently described in ameloblastomas or KRASG12V, recently described in adenomatoid odontogenic tumors. Conclusion: b-Catenin gene mutation persists as the pivotal alteration reported in CCOTs. This study gives further support to the concept that odontogenic tumors do not share a common genetic event and each tumor type shows a specific molecular profile. (CNPq # 165805/2015-3 and FAPEMIG).
RP77 - IN VIVO AND IN VITRO EFFECTS OF CURCUMIN ON HEAD AND NECK CARCINOMA: A SYSTEMATIC REVIEW. GABRIEL ÁLVARES BORGES, DANIELA FORTUNATO RÊGO, DANIELE XAVIER ASSAD, RICARDO DELLA COLETTA, GRAZIELA DE LUCA CANTO, ELIETE NEVES DA SILVA GUERRA. Head and neck squamous cell carcinoma (HNSCC) causes globally a high number of deaths. Therefore, more effective and less deleterious therapies are required. In this sense, the study of phytochemicals points to their use as chemo-preventive agents. All considered, the objective of this systematic review was to investigate the effects of curcumin on proliferation and survival of HNSCC. This study was based on the PRISMA Checklist. The search was conducted on 6 databases: Cochrane, LILACS, MEDLINE, PubMed, Web of Science and EMBASE. In vitro and in vivo studies that evaluated the effects of curcumin on cell viability, tumor growth, cell cycle or cell death in HNSCC cell lines or animal models were selected. Out of 387 gathered studies, 30 met the inclusion criteria. These studies demonstrated that curcumin induces cytotoxicity, intrinsic pathway apoptosis and G2/S-arrest in HSNCC cells. It also reduces tumor measurements in animal models. These events were mostly studied with MTT assay, flow cytometry and expression of cell cycle and apoptosis-related proteins. This systematic review demonstrated that curcumin has effect on HNSCC cell proliferation and survival, reinforcing the currently available evidence that it could be an effective adjuvant drug in HNSCC treatment.
RP78 - CLINICOPATHOLOGIC STUDY BETWEEN ORAL LEUKOPLAKIA AND PROLIFERATIVE VERRUCOUS LEUKOPLAKIA. DARCY FERNANDES, CLÁUDIA MARIA NAVARRO, MIRIAN APARECIDA ONOFRE, ELAINE MARIA SGAVIOLI MASSUCATO, ANDREIA BUFALINO. Proliferative verrucous leukoplakia (PVL) is a subtype of oral leukoplakia (OL), being characterized by multifocal presentation, resistance to treatment and a high rate of malignant transformation.