Epithelial-mesenchymal transition-like events in vulvar cancer and its relation with HPV

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) still remains an obscure event in vulvar squamous cell carcinoma (VSCC). METHODS: Immunohistochemistry (IHC) expression of E-cadherin, β-catenin, Snail, Slug, Twist and Vimentin was analysed in 87 VSCC, controlled for human papillomavirus (HPV) positivity, considering tumour front and central tumour as different morphological categories from the same tumour. RESULTS: Lower β-catenin and higher Vimentin expression was associated with invasive front when compared with the central tumour (P=0.013 and P⩽0.001, respectively). Higher expression of E-cadherin in central tumour was significantly related to absence of vascular and perineural invasion, lower invasion depth and ⩽2 lymph node involvement. Loss of β-catenin and high Slug, Snail and Twist expression was associated with HPV-negative tumours. Moreover, β-catenin lower expression associated with gain in Slug expression predicts a subgroup with worst outcome (P=0.001). Lower expression of β-catenin in both central tumour and invasive front correlated with lower overall survival (P=0.021 and P=0.011, respectively). Also, multivariate analysis showed that lower β-catenin expression was independently associated with poorer outcome (P=0.044). CONCLUSION: Human papillomavirus-related tumours show better prognosis and outcome; besides, they do not progress through EMT phenomenon. Immunohistochemical analysis of β-catenin in invasive tumour front is a key issue for establishing prognosis of vulva cancer.