Time series analysis of TP53 gene mutations in recurrent HPV-negative vulvar squamous cell carcinoma

The impact of TP53 gene mutations in recurrent HPV-negative vulvar squamous cell carcinomas is unclear. TP53 gene mutations were analyzed in archival tissues of 24 primary squamous cell carcinoma and local vulvar recurrences arising in chronic inflammatory dermatoses by analyzing the full coding sequence of the TP53 gene and correlated with disease-free survival. After resection of the primary squamous cell carcinoma with clear margins 19/24 patients had one and 5/24 had multiple recurrences. The first recurrence occurred after median of 46 months (range 12-180 months). In all, 17/24 (71%) primary squamous cell carcinomas had TP53 gene mutations and recurred after median disease-free intervals of 33 months (range 12-180). 14/17 (88%) recurrent squamous cell carcinomas carried again TP53 gene mutations, five with identical and nine with different, more complex TP53 gene mutations. 7/24 (29%) patients with a p53 wild-type primary SCC had the first recurrence after median 65 months (range 14-144) featuring p53 wild-type in 3/7 (43%) and TP53 gene mutations in 4/7 (57%) recurrent squamous cell carcinomas. Disease-free intervals of > 5 years (60-180 months) were observed in 10/24 patients total (42%; equally divided among p53 wild-type (5/7; 71%) and TP53 gene mutated (5/17; 29%) squamous cell carcinomas). In summary, squamous cell carcinomas recurred in the residual vulvar dermatosis independent of TP53 gene mutational status of the primary squamous cell carcinoma. The majority of TP53 gene mutated cancers recurred with different TP53 gene mutations, some of them more complex, and patients with p53 wild type developed TP53 gene mutations in the recurrent squamous cell carcinomas, possibly indicating increased genetic instability in longstanding chronic inflammatory dermatoses. A change of TP53 gene mutational status after > 5 years suggests de novo oncogenic events/carcinogenesis. Longer disease-free intervals in patients with p53 wild-type primary squamous cell carcinoma suggest that TP53 gene mutational status may serve as a prognostic marker for disease-free intervals.