p73 is over-expressed in vulval cancer principally as the δ2 isoform

Abstract

p73 was studied in squamous cancers and precursor lesions of the vulva. Over-expression of p73 occurred commonly in both human papillomavirus (HPV)-positive and -negative squamous cell cancers (SCC) and high-grade premalignant lesions. Whereas expression in normal vulval epithelium was detected only in the basal and supra-basal layers, expression in neoplastic epithelium increased with grade of neoplasia, being maximal at both protein and RNA levels in SCC. p73 Δ2 was the principal over-expressed isoform in the majority of cases of vulval SCC and often the sole form expressed in SCC. Over-expression of p73 was associated with expression of HPV-encoded E7 or with hypermethylation or mutation of p16 INK4a in HPV-negative cases. There was a close correlation between expression of p73 and p14 ARF in cancers with loss of p53 function. The frequent over-expression of p73 Δ2 in neoplastic but not normal vulval epithelium, and its co-ordinate deregulation with other E2F-1 responsive genes suggests a role in the oncogenic process. © 2001 Cancer Research Campaign.