Vulvar squamous cell carcinoma is a multifactorial disease following two separate and independent pathways
ABSTRACT Two separate pathways leading to vulvar carcinoma have been suggested. First, a human papillomavirus (HPV)-dependent pathway, in which premalignant stages of vulvar cancer are the classic vulvar intraepithelial neoplasia (VIN) lesions. Second, an HPV-independent pathway, associated with differentiated VIN III lesions and/or lichen sclerosus. To obtain insight into the mechanisms underlying these pathways, we determined the relationship between HPV DNA and the expression of p14(ARF) and p16(INK4A) in non- and (pre)malignant vulvar lesions. Seventy-three archival samples of non- and (pre)neoplastic vulvar lesions were selected and tested for hr-HPV DNA using a broad-spectrum HPV detection/genotyping assay (SPF(10)-LiPA) and the expression of p14(ARF) and p16(INK4A). The prevalence of HPV increased with the severity of the classic VIN lesions; in VIN I no hr-HPV was detected, in VIN II 43%, and in VIN III 71% of the samples were hr-HPV-positive. Roughly the same was true for the expression of p14(ARF) and p16(INK4A). The simultaneous expression of p14(ARF) and p16(INK4A) was highly associated with the presence of hr-HPV DNA. Hr-HPV was detected in only a single case of the differentiated VIN III lesions, whereas no expression of p14(ARF) was found and 16(INK4A) was present in only two cases. All 16 samples of vulvar cancer were hr-HPV DNA- negative, although in respectively 63% and 25%, p14(ARF) and p16(INK4A) was expressed. No relation was found between hr-HPV and the expression of p14(ARF) and p16(INK4A) in the 20 nonneoplastic vulvar lesions. Our results provide further evidence that vulvar squamous cell carcinoma is a multifactorial disease that develops from two different pathways. First, an HPV-dependent pathway with a remarkable resemblance to CIN lesions and cervical carcinoma and second, an HPV-independent pathway in which differentiated VIN III lesions that are hr-HPV-negative may be precursors.
- SourceAvailable from: Marjolijn (Jolijn) D Trietsch
[Show abstract] [Hide abstract]
- "The second type is typically seen in elderly patients and seems to develop independently from HPV infection. The HPV-independent type of carcinoma is associated with lichen sclerosis and mutations in the TP53 gene, but its etiology is much less well understood than the HPV-positive type  . "
ABSTRACT: Background Two etiologic pathways of vulvar cancer are known, a human papillomavirus (HPV)- and a TP53-associated route, respectively, but other genetic changes may also play a role. Studies on somatic mutations in vulvar cancer other than TP53 are limited in number and size. In this study, we investigated the prevalence of genetic mutations in 107 vulvar squamous cell carcinomas (VSCCs). Methods A total of 107 paraffin-embedded tissue samples of primarily surgically treated VSCCs were tested for HPV infection and screened for mutations in 14 genes (BRAF, CDKN2A(p16), CTNNB1, FBXW7, FGFR2, FGFR3, FOXL2, HRAS, KRAS, NRAS, PIK3CA, PPP2R1A, PTEN, and TP53) using Sanger sequencing and mass spectrometry. Results Mutations were detected in 7 genes. Of 107 VSCCs, 66 tumors (62%) contained at least one mutation (TP53 = 58, CDKN2A(p16) = 14, HRAS = 10, PIK3CA = 7, PPP2R1A = 3, KRAS = 1, PTEN = 1). Mutations occurred most frequently in HPV-negative samples. Five-year survival was significantly worse for patients with a mutation (47% vs 59%, P = .035), with a large effect from patients carrying HRAS-mutations. Conclusion Somatic mutations were detected in 62% of VSCCs. As expected, HPV infection and TP53-mutations play a key role in the development of VSCC, but CDKN2A(p16), HRAS, and PIK3CA-mutations were also frequently seen in HPV-negative patients. Patients with somatic mutations, especially HRAS-mutations, have a significantly worse prognosis than patients lacking these changes, which could be of importance for the development of targeted therapy.Gynecologic Oncology 10/2014; 135(1). DOI:10.1016/j.ygyno.2014.07.094 · 3.69 Impact Factor
[Show abstract] [Hide abstract]
- "LS is a chronic inflammatory disease of the vulvar skin and mucosa characterized by markedly thinned epithelium with loss of rete ridges, culminating in architectural changes of the vulva, and can give rise to severe itching. Differentiated VIN (dVIN) is thought to play a role in this HPV-independent pathway as a premalignant lesion with a high malignant potential, although the molecular pathogenesis remains elusive . Women with LS have a 2% to 6% lifetime risk to develop vulvar SCC . "
ABSTRACT: The molecular pathogenesis of human papilloma virus-unrelated vulvar squamous cell carcinoma is not well known. Whether malignant progression of lichen sclerosus and differentiated vulvar intraepithelial neoplasia to vulvar squamous cell carcinoma could be accompanied by altered DNA content has not been studied extensively. DNA content in isolated nuclei of microdissected normal vulvar epithelium (n = 2), lichen sclerosus (n = 9), differentiated vulvar intraepithelial neoplasia (n = 13), and squamous cell carcinoma (n = 17) from 22 patients was measured via DNA image cytometry. For additional analysis, 6 differentiated vulvar intraepithelial neoplasia lesions were selected, bringing the number of patients to 28. p53 expression was determined by immunohistochemistry on consecutive tissue sections. Thirty-eight percent (5/13) of differentiated vulvar intraepithelial neoplasia lesions and 65% (11/17) of squamous cell carcinomas were DNA aneuploid or tetraploid. In lesions that contained differentiated vulvar intraepithelial neoplasia and adjacent squamous cell carcinoma, the ploidy status of differentiated vulvar intraepithelial neoplasia did not exceed that of squamous cell carcinoma. We observed a strong correlation between high p53 expression and DNA aneuploidy. This relation was also present at the level of a single nucleus, measured by sequential image cytometry of p53 immunohistochemistry followed by DNA image cytometry on formalin-fixed tissue sections. Similarly, we found p53-positive nonproliferating cells with increased DNA content in the superficial compartment of 6 additional solitary differentiated vulvar intraepithelial neoplasia lesions that were not associated with squamous cell carcinoma, indicating ascending aneuploid cells from the basal compartment. DNA ploidy measurements suggest that differentiated vulvar intraepithelial neoplasia has a higher malignant potential than lichen sclerosus and thus is a more likely precursor of squamous cell carcinoma. Furthermore, high p53 expression correlates with increased DNA content and aneuploidy; but it requires further research to unveil a possible causal relation.Human pathology 10/2010; 41(10):1475-85. DOI:10.1016/j.humpath.2009.12.015 · 2.81 Impact Factor