RESUMEN

Epigenetic DNA methylations plays an important role in oral carcinogenesis. The soluble frizzled receptor protein (SFRP) family together with WIF-1 and DKK-3 encodes antagonists of the WNT pathway. Silencing of these genes leads to constitutive WNT signalling. Because aberrant expression of beta-catenin might be associated with the epigenetic inactivation of WNT inhibitors, we analyzed, in a collection of primary OSCC with matched normal oral mucosa, the methylation status of a complete panel of genes, SFRP-1, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3, that are involved directly and indirectly in WNT pathway, in order to demonstrate WNT-pathway activation in the absence of beta-catenin and/or APC/Axin mutations during oral carcinogenesis. Methylation-specific PCR (MSP) was performed to study inactivation of SFRP-1, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3 genes in 37 cases of paraffin embedded oral cancer. This study showed that the methylation is an important epigenetic alteration in oral cancer. In particular, SFRP-2, SFRP-4, SFRP-5, WIF-1, DKK-3 revealed methylation status of their promoter in OSCC, whereas SFRP-1 showed demethylation in cancer. Fisher's exact test revealed statistically significant results (p<0.05) for all genes. The Wald test confirmed the statistically significant association between SFRP2-4-5 gene methylation and OSCC (p<0.05). SFRP-1 was also characterized by a different statistically significant epigenetic behaviour, because of it was demethylated in cancer (p<0.05). Statistical regression test showed high levels of sensitivity, specificity and accuracy for SFRP genes, while WIF-1 and DKK-3 have reportedly high specificity, moderate accuracy but low sensitivity. This study suggests that a cause of catenin delocalization in oral cancer could be due to WNT pathway activation, by epigenetic alterations of SFRP, WIF-1 and DKK-3 genes.

Asunto(s)

Carcinoma de Células Escamosas/genética , Metilación de ADN/genética , Epigénesis Genética , Neoplasias de la Boca/genética , Transducción de Señal/genética , Proteínas Wnt/genética , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/genética , Carcinoma de Células Escamosas/metabolismo , Quimiocinas , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Femenino , Humanos , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Persona de Mediana Edad , Neoplasias de la Boca/metabolismo , Reacción en Cadena de la Polimerasa , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Curva ROC , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Sensibilidad y Especificidad , Proteínas Wnt/metabolismo