International Journal of Molecular Sciences 2020; 21(21)

p53 Immunohistochemical Patterns in HPV-Independent Squamous Cell Carcinomas of the Vulva and the Associated Skin Lesions: A Study of 779 Cases.

Rakislova N, Alemany L, Clavero O, Saco A, Torné A, del Pino M, Munmany M, Rodrigo-Calvo MT, Guerrero J, Marimon L, Vega N, Quirós B, Lloveras B, Ribera-Cortada I, Alejo M, Pawlita M, Quint W, de Sanjosé S, Ordi J, Vvap Study Group
- i: - TP53 - TP53 content: - "Human papillomavirus (HPV)-independent vulvar squamous cell carcinomas (VSCC) and its precursors frequently harbour " - " mutations. Recently, six p53 immunohistochemical (IHC) patterns have been defined, which have shown strong correlation with " - " mutation status. However, few studies have applied this new six-pattern framework and none of them exhaustively compared p53 IHC positivity and patterns between invasive VSCC and adjacent skin lesion. We performed p53 IHC in a series of 779 HPV-independent VSCC with adjacent skin and evaluated the IHC slides following the newly described classification. Some 74.1% invasive VSCC showed abnormal p53 IHC staining. A skin lesion was identified in 450 cases (57.8%), including 254 intraepithelial precursors and 196 inflammatory/reactive lesions. Two hundred and ten of 450 (47%) VSCC with associated skin lesions showed an abnormal p53 IHC stain, with an identical staining pattern between the VSCC and the adjacent skin lesion in 80% of the cases. A total of 144/450 (32%) VSCC showed wild-type p53 IHC both in the invasive VSCC and adjacent skin lesion. Finally, 96/450 (21%) VSCC showed p53 IHC abnormal staining in the invasive VSCC but a wild-type p53 staining in the skin lesion. Most of the discordant cases (70/96; 73%) showed adjacent inflammatory lesions. In conclusion, the p53 IHC staining and pattern are usually identical in the VSCC and the intraepithelial precursor."