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:  Beta‐papillomaviruses (beta‐HPV) have been linked to the development of skin cancer in humans. Because both E6 and E7 proteins from beta‐HPV have been involved in the potential carcinogenicity of these viruses, we investigated their role on UVB‐induced apoptosis in HaCaT cell line. HaCaT cells have been transduced with both E6/E7 using a retroviral system and treated with PRIMA‐1. Apoptosis was assessed by flow cytometry to measure mitochondrial membrane potential and DNA fragmentation. HaCat keratinocytes transduced with both E6 and E7 genes of seven beta‐HPV types (HPV5, HPV8, HPV14, HPV24, HPV36, HPV38 and HPV49) did not demonstrate any inhibition of UVB‐induced apoptosis, even after p53 reactivation through PRIMA‐1. Our data suggest that the expression of E6 and E7 exert different modulatory effects on UVB‐induced apoptosis according to beta‐HPV types and to the cellular genetic context.

References1 Rubegni P, Burroni M, Sbano P, Andreassi L. Digital dermoscopy analysis and internet-based program for discrimination of pigmented skin lesion dermoscopic images. Br J Dermatol 2005; 152:395-6. 2 Oka H, Hashimoto M, Iyatomi H et al. Internet-based program for automatic discrimination of dermoscopic images between melanomas and Clark naevi. Br J Dermatol 2004; 150:1041 (Letter). SIR, We read with interest the recent article by La Placa et al. 1 investigating the detection of high-risk (HR) mucosal human papillomavirus (HPV) in primary melanoma (PM) and in acquired dysplastic melanocytic naevi. Using two different polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay methods, the authors found HR HPV genotypes in 24% of acquired dysplastic melanocytic naevi and in 27% of 14 PMs compared with 0% in the control skin samples. However, we wish to make the following comments. Five of 14 melanoma patients positive for HPV DNA were aged over 67 years, and there is evidence showing an association between HPV infection and ageing in immunocompetent patients or in patients with a history of cutaneous skin cancer. 2 Only three studies 3-5 regarding the association between melanoma and HPV are available. First, using a nonspecific polyclonal antibody raised against bovine papillomavirus 1, Dreau et al. 3 found HPV in 58% of 12 melanomas. Then, using PCR followed by sequencing, Miracco et al. 4 observed only one case among 54 malignant melanomas of mucosal HR HPV-16 DNA.Finally, seroreactivity to HPV-16 was studied in 84 patients with malignant melanoma and no association for HPV-16 serorecognition was found. 5 A significant problem for investigations of an association between HPV and skin cancer is that HPV is part of the microbiological flora of healthy human skin. Indeed, high detection rates (25-65%) of both HR mucosal and cutaneous HPV DNA have been found in healthy skin biopsies, plucked hairs and skin swab samples in large series of immunocompetent individuals. 6 An impressive diversity of known HPV types or putative novel types was identified by sequencing. In general, higher detection rates were found with primers detecting epidermodysplasia verruciformis-related HPV types compared with primers allowing the detection of mucosal DNA HPV. However, HR HPV DNA, especially oncogenic HPV-16, is frequently detected in distal digital and periungual skin in contrast to other skin areas, suggesting a genital-digital mode of transmission. 7 Thus, skin HPVs represent ubiquitous viruses, highly prevalent in the normal skin of healthy adults and causing asymptomatic infections likely to be acquired very early in infancy. 8 This may suggest a commensalic nature, and HPV positivity in skin tumours may merely reflect contamination of the tumours by viral HPV DNA or by particles harboured in cells shed from infected healthy skin. 9 It should be noted that in all previous studies regarding the presence of HPV in malignant melanoma, no sample of normal skin from the same patients was investigated.Altogether, the ex...