Sillanpää et al., pp. 1792–1799 Members of the matrix metalloproteinase (MMP) family have been associated with advanced-stage cancer and contribute to tumor progression, invasion and metastasis. But in some tumor types MMP-7, the smallest member of the clan, may be a notable exception. Sillanpää and colleagues found that overexpression of MMP-7 in epithelial ovarian cancer serves as an independent prognostic factor that predicts longer survival. The authors immunohistochemically determined the expression of MMP-7, also known as matrilysin and evaluated its relation to patient survival in 284 primary epithelial ovarian cancers, their 36 metastases, and 8 normal ovaries. Malignant cells of epithelial origin expressed MMP-7, even though in most cases the intensity was relatively weak and comparable to expression levels in the surface epithelial cells of normal ovaries. While MMP-7 expression appears to be an inherent feature of ovarian cancer, high levels did not promote tumor progression, quite the opposite. Ten-year disease-related survival was significantly better when the percentage area of MMP-7 expression in cancer cells was high, when compared to low (p = 0.0008). Previous studies on breast cancer and lung cancer have not revealed any significant correlation between the expression of MMP-7 and standard prognostic factors. On the other hand, several studies on gastrointestinal carcinomas have suggested that high MMP-7 expression in cancer cells predicts shortened survival. The current study emphasizes that MMP-7 eludes easy categorization and may play different roles in different cancers and specific tumor stages. Pothlichet et al., pp. 1869–1877 Genetic lesions together with epigenetic alterations drive tumor progression in a multi-step process. Melanoma-associated retrovirus (MelARV) single-handedly accomplishes both. It not only induces mutations through insertions but also suppresses immunosurveillance in the host report Pothlichet and colleagues in their current study. All mammalian genomes contain normally silent, endogenous retroviruses (ERV) that are part of the host's genetic heritage. One of them, MelARV, is active in the B16 spontaneous melanoma of C57BL/6 mice and has been directly linked to tumorigenesis in vitro. Taking advantage of a previously isolated and highly metastatic subline, B16F10, the authors analyzed the MelARV proviruses present in the B16 melanoma and compared the insertion sites in both cell lines to determine whether insertional mutagenesis contributes to tumorigenesis in vivo. They not only identified the active progenitor ERV copy but also detected 2 new insertions sites in the B16F10 subline. Interestingly, both insertions occurred within active genes that previously had been linked to the metastatic potential of tumor cells. In the case of integrin alpha 2 (itga2) the insertion resulted in a 5- to 6-fold decrease in transcript level while in the case of docking protein 5 (dok5), the newly inserted MelARV copy increased transcript levels 29-fold. Surprisingly, both cell lines express very high levels of provirus. The authors speculate that this activity is maintained to reap the immunosuppressive activity of the envelope protein gene. Further studies are necessary to determine if these properties of activated endogenous retroviruses are also relevant to the development of tumors in human hosts. Vaccarella et al., pp. 1934–1939 In the past, the majority of studies on genital human papillomavirus (HPV) infections focused on women and the associated cervical cancer risk. This concentrated research effort led to the successful development of a highly efficacious vaccine, which was recently approved by the FDA. HPV infects both genders, yet extensive studies on HPV prevalence in the general male population are still rare. Vaccarella and colleagues set out to fill the void and conducted one of the largest studies ever undertaken, which - unlike most others - was not restricted to young men. Among 779 men who requested a vasectomy in 14 states of Mexico, 8.7% overall tested positive for any type of HPV, while the prevalence among the most sexually active men almost doubled to 14.9%. The most commonly found HPV types were, in descending order, HPV59, 51, 16 and 58. Although the overall prevalence and age-distribution resembled women's infection rates, the type-specific distribution differed significantly. HPV59 is rarely found in women, in whom HPV16 dominates instead. Maybe not surprisingly, condom use and circumcision reduced the risk of HPV infection. Vaccinating men and women could be the best way to prevent the spread of the cancer-causing virus among women in cultures, where trying to prevent sexually transmitted infections is equated with promiscuity. Tailoring the vaccine to prevent disfiguring genital warts in men might be key to increase the acceptance of the vaccine among the male population and learning more about HPV infections in men is an important prerequisite.