Ethel-Michele de Villiers

Prevailing papillomavirus types in non-melanoma carcinomas of the skin in renal allograft recipients.

The role of human papillomavirus (HPV) in the aetiology of in situ and invasive carcinoma of the genital tract is well established. In the rare disorder epidermodysplasia verruciformis (EV), in which patients develop extensive warts of unusual types and multiple cutaneous squamous cancers on light‐exposed skin, current evidence suggests a probable role for a specific group of EV HPVs in the carcinogenic process. Determination of the possible role of HPV in the aetiology of non‐melanoma skin cancers (NMSCs), which occur frequently in immunosuppressed organ allograft recipients, has been limited, until recently, by the lack of availability of a sensitive detection system for a wide range of cutaneous HPV types. We have used a combination of 2 sets of PCR primers to examine 68 benign and malignant tumours collected over a 12‐year period from 25 renal allograft recipients. Cloning and sequencing of the PCR products were carried out to distinguish HPV DNA from cellular sequences. A combination of these techniques revealed HPV DNA in all viral warts, 65% of keratoses, 91% of intra‐epidermal cancers and 91% of invasive squamous cancers. Both cutaneous and EV HPV types were detected, including 18 novel types. In 4 patients with multiple cancers, the most prevalent types were in the EV group: HPV 20, 23, 38 and 2 novel types, DL40 and DL267 (related to HPV 10 and 38, respectively). These 5 HPV types were present in a total of 73% of all malignant lesions tested. The technique described represents a reliable method of HPV DNA detection in NMSC. The EV group of HPVs predominate in the cancers, but the multiplicity of HPV types detected with double infection in some lesions suggests virus/virus in addition to virus/host interaction in the carcinogenic process. Int. J. Cancer 73:356–361, 1997.

Esophageal squamous cell cancer in patients with head and neck cancer: Prevalence of human papillomavirus DNA sequences.

An etiologic role for human papillomavirus (HPV) infections in either head and neck (HNC) or esophageal carcinogenesis remains debatable. Patients with head and neck cancer are at high risk for developing a second esophageal squamous cell cancer (ESCC). The aim of our study was to determine whether HPV infections play a role in this multifocal carcinogenesis. Samples from 2 groups of HNC patients were studied: Random esophageal biopsies were collected from the first group of 60 patients who had been screened for asymptomatic ESCC. The second group consisted of 21 patients with pairs of HNC and ESCC. Both the fresh frozen biopsy samples of the first group and the paraffin‐embedded specimens of the second group were evaluated for the presence of HPV DNA sequences by PCR amplification, cloning and sequencing. HPV DNA sequences were detected in 66.7% of normal/inflammatory (34/51) and dysplastic and malignant (6/9) esophageal tissues from HNC patients being screened endoscopically. Similarly, in the second group of 21 patients with both HNC and ESCC, HPV DNA sequences were demonstrated in 13 (61.9%) of the HNC biopsies and in 14 (66.7%) of the ESCC biopsies. The prevalence of high‐risk‐type HPV 16 was low (5/51, 9.8%) in normal/inflammatory esophageal mucosa but higher (10/24, 47.6%) in ESCC. The low‐risk HPV 11 was present in 37.3% (19/51) of normal/inflammatory, 66.7% (4/6) of dysplastic and 28.9% (13/45) of the carcinoma samples. The same HPV type was present in only 3/21 pairs of HNC and ESCC samples, suggesting that a clonal expansion from the HNC to a subsequent ESCC, or visa versa, is unlikely. The high prevalence of “low‐risk” HPV infections points to the need for studies on possible interactions of these infections with the use of alcohol and tobacco in the pathogenesis of these tumors.

Subclinical Human Papillomavirus Infections in Male Sexual Partners of Female Carriers

The male sexual partners of 156 women with human papillomavirus infection of the cervix uteri were examined. In 120 men (77 per cent) penile lesions were found on examination of the penis via a colposcope (peniscopy) the most common of which were flat acetowhite lesions (53 per cent). Predilection sites of lesions were the urethral meatus and the corona glandis (23 and 19 per cent of the lesions, respectively). Using filter in situ hybridization human papillomavirus-deoxyribonucleic acid was found in penile smears of 61 men (39 per cent). The cancer-associated viral types (human papillomavirus 16 and 18) were identified in 75 per cent of the human papillomavirus positive men. Viral types of sexual partners were identical in 87 per cent. The correlation between infections with human papillomavirus 16 and 18, and the severity of the cervical lesion was significant in corresponding sexual partners. Our results support the hypothesis that male sexual partners represent a risk factor by acting as a reservoir for genital infections with papillomaviruses. The majority of human papillomavirus infections are of subclinical character. They require sensitive diagnostic techniques, such as peniscopy and hybridization for their identification. Detection and treatment of subclinical human papillomavirus infection in men may be important for the prevention of genital cancer in women.

The Role of Papilloma Viruses in Human Cancer

Twelve types of papillomaviruses have been isolated thus far from papillomatous and Bowenoid lesions of the human genital tract.Four types, HPV 6, 11, 16 and 18 are most frequently found. HPV 6 and 11 cause the typical genital warts (condylomata acuminate) and mild dysplastic lesions of the cervix characterized by a high degree of koilocytotic atypia. HPV 16 and 18 are preferentially found in Bowenoid papulosis and Bowen’s disease at external genital sites. Moderate and severe cervical dysplasias with little or no koilocytosis appear to be common manifestations of these infections at cervical sites. HPV 16 is found in approximately 50% of all cervical, penile and vulvar cancers, HPV 18 in close to 20%. The majority of the remaining tumours reveals evidence for infections with additional types of papillomaviruses. Several cell lines have been identified containing either HPV 18 or HPV 16 genomes. The state of viral DNA in Bowenoid precursor lesions differs from that of cervical carcinomas. The former contain episomal DNA whereas integration seems to be a regular event in carcinomas. Integration regularly affects the El–E2 open reading frames of HPV 16 or 18 DNA. Fusion transcripts from the integrated HPV DNA (E6–E7 region) and adjacent host cell DNA have been documented. The available data support a causative role of specific HPV infections in the etiology of human genital cancer.

Isolation of two virus-like circular DNAs from commercially available milk samples

ABSTRACT Epidemiological data indicate a potential relationship between milk and dairy product consumption and the incidence of breast cancer, as well as neurodegenerative diseases. We report the isolation of two novel circular DNA molecules isolated from commercially available milk.

Specific Nutritional Infections Early in Life as Risk Factors for Human Colon and Breast Cancers Several Decades Later: Nutritional Infections, Colon- and Breast Cancers

Introduction Red meat and dairy products are currently been considered as risk factors for colon, breast, lung and a few additional cancers (recent reviews Ref. 1,2). Our group postulated a specific relationship of these cancers to infections by meat and milk consumption obtained from Aurochs-derived Eurasian dairy cattle the global epidemiological patterns of colon and breast cancer incidence points to a close relation to the consumption of products originating from these specific breeds of cattle. The suggested species-specific risk triggered the hypothesis that infections derived from these types of cattle may represent the donors of, at that time, still undefined infections resulting from the nutritional uptake of infected meat and milk products. This stimulated the initiation of an analysis of 120 sera obtained from individual dairy cows, from commercially available dairy products and several human sera from multiple sclerosis patients, chronic human diseases and healthy blood donors. Initially the isolation of 20 different genomes of single-stranded circular DNA was published. After their classification into four groups, we designated them as bovine meat and milk factors (BMMF). The first two groups (BMMF1 and BMMF2) have been more intensively analyzed – specific types of group 1, presently 13 in number, and 95 distinguishable types in group 2 (de Villiers et al., unpublished results). Since most of them show similarity in nucleotide sequences to specific bacterial plasmids, mainly of Acinetobacter baumannii, we ruled out the possibility of a laboratory contamination with bacterial DNA by transfecting several of the isolated molecules into human cells. The transfected DNA was transcriptionally active and replicated autonomously in specific types of human cell lines. Recently, evidence emerged linking specific types of BMMF1 and 2 to colon cancer development, acting as specific triggers for random mutations in target cells for malignant conversion (Bund et al., unpublished results). This triggering results from chronic inflammatory foci in the lamina propria close to the Lieberkühn crypts of the colon. These foci produce reactive oxygen species (ROS) which induce mutations within the rapidly replicating adjacent Ki67 positive crypt cells, but seem to leave the nonreplicating cells within the foci (Ki67 negative) unaffected (Bund et al. unpublished results). The present contribution attempts to link existing data on BMMF infections with reported protective effects related to prolonged breast-feeding periods. Many reports claim such effects for newborns, as well as for the nursing mothers. In addition, prolonged intake of nonsteroidal anti-inflammatory drugs (NSAID) protects against some of the same cancers. Here we present the view that blocking of receptors by sugars, selectively found in human milk, protect against specific infectious agents and cancers. In the chronic persistent inflammatory lesions caused by BMMFs, NSAIDs should act defensively by interfering with the mode of action of such inflammations.

Dairy cattle serum and milk factors contributing to the risk of colon and breast cancers: Cancer risk due to bovine factors

The analysis of published epidemiological data on colon and breast cancer reveals a remarkable concordance for most regions of the world. A low incidence for both cancers has been recorded in Mongolia and Bolivia. Discrepant data, however, have been reported for India, Japan and Korea. In India, the incidence of breast cancer is significantly higher than for colon cancer, in Japan and Korea colon cancer exceeds by far the rate of breast cancer. Here, studies are summarized pointing to a species‐specific risk for colon cancer after consumption of beef originating from dairy cattle. Uptake of dairy products of Bos taurus‐derived milk cattle, particularly consumed at early age, is suggested to represent one of the main risk factors for the development of breast cancer. A recent demonstration of reduced breast cancer rates in individuals with lactose intolerance (Ji et al., Br J Cancer 2014; 112:149‐52) seems to be in line with this interpretation. Species‐specific risk factors for these cancers are compatible with the transmission of different infectious factors transferred via meat or dairy products. Countries with discordant rates of colon and breast cancer reveal a similar discordance between meat and milk product consumption of dairy cattle. The recent isolation of a larger number of novel presumably viral DNAs from serum, meat and dairy products of healthy dairy cows, at least part of them infectious for human cells, deserves further investigation. Systemic infections early in life, resulting in latency and prevention of subsequent infections with the same agent by neutralizing antibodies, would require reconsideration of ongoing prospective studies conducted in the adult population.