Differential etiopathogenic features of vulvar squamous cell carcinomas in sub-Saharan Africa and Europe

Abstract

Two pathways have been described for vulvar squamous cell carcinomas (VSCC), one associated with human papillomavirus (HPV), and the other HPV-independent. We compared the etiopathogenic features of a series of VSCC from Mozambique, a sub-Saharan country with high prevalence of HPV and HIV, with those of Spain, a European country with low prevalence of HPV and HIV. All VSCC diagnosed at the two institutions from January 2018 to December 2020 were included (n = 35 and n = 41, respectively). HPV DNA detection and genotyping, and immunohistochemistry for p16 and p53 were performed. Tumors showing p16 positive staining and/or HPV DNA positivity were considered HPV-associated. 34/35 tumors (97%) from Mozambique and 8/41 (19%) from Spain were HPV-associated (P < .001). Mean age of the patients from Mozambique and Spain was 45 ± 12 and 72 ± 14, respectively (P < .001). No differences were found in terms of HPV genotypes or multiple HPV infection rates. 1/35 tumors (3%) from Mozambique and 29/41 (70%) from Spain showed abnormal p53 immunostaining (P < .001). In contrast with the predominance of HPV-independent VSCC affecting old women in Europe, most VSCC in sub-Saharan Africa are HPV-associated and arise in young women. This data may have important consequences for primary prevention of VSCC worldwide.

Keywords: HPV; Mozambique; Spain; p16; p53; vulvar cancer.

FIGURE 1

A characteristic example of each of the two types of vulvar squamous cell carcinoma (VSCC), HPV‐associated and HPV‐independent. The former being predominant in sub‐Saharan countries such as Mozambique and the latter in European countries such as Spain. (A) HPV‐associated invasive VSCC (H&E ×200) with basaloid histology, positive p16 staining (A') and wild‐type p53 staining showing mid‐epithelial pattern (A"). (B) HPV‐independent invasive VSCC (H&E ×200) with keratinizing histology, negative p16 staining (B') and abnormal p53 staining showing overexpression pattern (B")