Human cancers and human viruses

Inflammation initiates cancer by depleting stem cells

According to the theory presented herewith, neoplasia results solely from stem cell depletion. Besides serving as tissue progenitors, stem cells are postulated to secrete a vital substance 'A' necessary for proper tissue function. Carcinogens interfere with 'A' production mainly by destroying stem cells and since the latter are not replenished, less 'A' is produced. In order to repair the deficiency, the organism grows a special organ, the neoplasm, dedicated to produce a substitute, denominated here as substance 'B'. Since carcinogens continue depleting stem cells, the neoplasm has to grow more and more in order to keep up with the demand, until reaching a stage of decompensation when the harm inflicted by it is greater than its benefit. Any stem cell depleting substance or process e.g. ablation, chemotherapy and inflammation, is regarded here as a carcinogen. Even animal tumor viruses are postulated here to exert their harm mainly by depleting stem cells. Protracted inflammation e.g. ulcerative colitis or cystic mastopathy, hits stem cells and is followed therefore by neoplasia. Age specific incidence rates of such pathologies resemble precursor-successor curves of tracer kinetics. The precursor inflammation hits young adults, while its successive neoplasia is more prevalent in older individuals. Although most age specific curves of adult cancers are unimodal, at least five are bimodal, resembling precursor-successor curves. These are: Hodgkin's disease, seminoma, nasopharyngeal and retroperitoneal tumors and cancer of bone and joints. It is suggested here that these age specific curves are mixtures of two pathologies, an inflammatory, which is prevalent in young persons, followed by neoplasia.

Genital warts and cervical neoplasia: an epidemiological study

Cervical carcinoma and cervical intra-epithelial neoplasia (CIN) are likely to be associated with all sexually transmitted diseases (STDs). To help discover which (if any) of the recognised STDs might actually cause these conditions, a key question is whether one particular such association is much stronger than the others. The present study is therefore only of women newly attending an STD clinic, and compares the prevalences of cytological abnormalities of the cervix among 415 women attending with genital warts, 135 with genital herpes, and 458 with trichomoniasis or gonorrhoea. Significantly more genital wart patients (8.1%) than trichomoniasis or gonorrhoea patients (1.9%) showed dyskaryotic changes (adjusted relative risk (RR) = 5.8 with 95% limits 2.5-13.5) at, or a few months before, first attendance, while no excess whatever was seen in women with genital herpes. Moreover, half the women had a subsequent smear (at an average of 3-4 years after first attendance) and, although the diagnosis at first attendance was not related to the onset rate of dyskaryotic changes observed in these subsequent smears, it was related to the onset rate of grade III cervical intra-epithelial neoplasia (CIN III), which was found in 7 previous genital wart patients, in 2 previous trichomonas patients, but in 0 previous genital herpes patients. Thus, our findings suggest that herpes is not directly relevant to dyskaryotic change, but that one or more of the human papilloma viruses that cause genital warts may be.