Heterogeneous etiology of squamous carcinoma of the vulva

Benign anal lesions, inflammatory bowel disease and risk for high-risk human papillomavirus-positive and -negative anal carcinoma

A central role in anal carcinogenesis of high-risk types of human papillomaviruses (hrHPV) was recently established, but the possible role of benign anal lesions has not been addressed in hrHPV-positive and -negative anal cancers. As part of a population-based case-control study in Denmark and Sweden, we interviewed 417 case patients (93 men and 324 women) diagnosed during the period 1991-94 with invasive or in situ anal cancer, 534 patients with adenocarcinoma of the rectum and 554 population controls. Anal cancer specimens (n = 388) were tested for HPV by the polymerase chain reaction. Excluding the 5 years immediately before diagnosis, men, but not women, with anal cancer reported a history of haemorrhoids [multivariate odds ratio (OR) 1.8; 95% confidence interval (CI) 1.04-3.2] and unspecific anal irritation (OR 4.5; CI 2.3-8.7) significantly more often than controls. Women with anal cancer did not report a history of benign anal lesions other than anal abscess to any greater extent than controls, but they had used anal suppositories more often (OR 1.5; CI 1.1-2.0). Patients with hrHPV in anal cancer tissue (84%) and those without (16%) reported similar histories of most benign anal lesions, but anal fissure or fistula was more common among hrHPV-positive cases. Ulcerative colitis and Crohn's disease, reported by <1% of study participants, were not associated with anal cancer risk. The higher proportion of hrHPV-positive anal cancers among case patients with anal fissure or fistula suggests that such mucosal lesions may provide direct viral access to basal epithelial layers. Since risk associations with benign anal lesions in men may be confounded by unreported sexual behaviour, and since risk associations in women were generally negative, it seems unlikely that benign anal lesions act as promoters in hrHPV-associated anal carcinogenesis. Moreover, benign anal lesions appear not to be linked to an alternative, hrHPV-unassociated causal pathway to anal cancer. Ulcerative colitis and Crohn's disease were not supported as causal factors for anal cancer.

Absence of p53 protein overexpression in precancerous lesions of the vulva

BACKGROUND

Recently the authors reported the prognostic value of p53 protein overexpression in invasive squamous cell carcinoma of the vulva. The aim of this study was to evaluate the status of p53 overexpression and human papillomavirus (HPV) infection in patients with precancerous lesions of the vulva.

METHODS

Biopsy specimens of 28 women (mean age, 44.2 years; range, 19-71 years) with warty and/or basaloid type vulvar intraepithelial neoplasia (VIN) of Grade 1 to 3 were examined retrospectively for p53 protein overexpression by immunohistochemistry. The presence of the HPV genome was assessed using a nested polymerase chain reaction (PCR) method with consensus primers directed against the L1 coding region.

RESULTS

Neither the preoperative punch biopsy specimen nor the subsequent surgical specimen contained immunohistochemically detectable levels of p53 in this study of a group of younger women with preinvasive vulvar lesions. These results are in contrast to those obtained previously in older women with keratinizing squamous cell carcinoma demonstrating p53 protein overexpression in approximately 50% of patients. HPV DNA was detected in the vast majority of VIN cases (92.8%) using a highly sensitive nested PCR method. The current data indicate that p53 protein is not overexpressed in basaloid/warty VIN when evaluated by immunohistochemistry. In addition, this study confirms previous reports demonstrating the presence of HPV DNA in the majority of these lesions.

CONCLUSIONS

These data suggest that p53 protein overexpression is not an early event in the pathogenesis of basaloid/warty type vulvar dysplasia and that HPV infection may contribute to the development of VIN.

Cofactors with human papillomavirus in a population-based study of vulvar cancer

BACKGROUND

Human papillomavirus (HPV) has been previously associated with vulvar cancer. In a population-based study, we examined whether exposure to HPV, cigarette smoking, or herpes simplex virus 2 (HSV2) increases the risk of this cancer.

METHODS

Incident cases of in situ (n = 400) and invasive (n = 110) squamous cell vulvar cancer diagnosed among women living in the Seattle area from 1980 through 1994 were identified. Serum samples were analyzed for antibodies against specific HPV types and HSV2. HPV DNA in tumor tissue was detected by means of the polymerase chain reaction. In most analyses, case subjects were compared with population-based control subjects (n = 1403). Relative risks of developing vulvar cancer were estimated by use of adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Increased risks of in situ or invasive vulvar cancer were associated with HPV16 seropositivity (ORs = 3.6 [95% CI = 2.6-4.8] and 2.8 [95% CI = 1.7-4.7], respectively), current cigarette smoking (ORs = 6.4 [95% CI = 4.4-9.3] and 3.0 [95% CI = 1.7-5.3], respectively), and HSV2 seropositivity (ORs = 1.9 [95% CI = 1.4-2.6] and 1.5 [95% CI = 0.9-2.6], respectively). When the analysis was restricted to HPV16 DNA-positive tumors (in situ or invasive), the OR associated with HPV16 seropositivity was 4.5 (95% CI = 3.0-6.8). The OR for vulvar cancer was 18.8 (95% CI = 11.9-29.8) among current smokers who were HPV16 seropositive in comparison with never smokers who were HPV16 seronegative.

CONCLUSIONS

Current smoking, infection with HPV16, and infection with HSV2 are risk factors for vulvar cancer. Risk appears particularly strong among women who are both current smokers and HPV16 seropositive.

Interlaboratory agreement among results of human papillomavirus type 16 enzyme-linked immunosorbent assays

Serological assays for measuring antibodies to human papillomavirus type 16 (HPV-16) virus-like particles (VLPs) have become important epidemiologic tools in recent years. However, the interlaboratory replicability of these assays has not been assessed. In this investigation, three laboratories tested a panel of specimens obtained from two different groups: 265 subjects in a vulvar cancer case-control study and 107 healthy volunteer blood donors. Each laboratory used an enzyme-linked immunosorbent assay (ELISA), but no attempt was made to standardize assay procedures among the three laboratories. The data showed good day-to-day intralaboratory replicability in laboratory 1 (correlation coefficient, > or = 0.88) and good intra-assay variability in laboratory 3 (correlation coefficient, > or = 0.93). Interlaboratory correlations, likewise, ranged between 0.61 and 0.80 in both case-control study subjects and healthy blood donors, indicating that ELISA optical density (OD) values between laboratories were linearly related regardless of the population. Kappa coefficients (kappa), based on each laboratory's categorical interpretation of its results (as positive or negative), showed good agreement (kappa, > 0.6) in case-control study subjects and moderate agreement (kappa, > or = 0.4) in blood donors, a population that had few strongly positive sera. When OD values near seropositive cutoffs were treated as indeterminates, there was little discordance between laboratories in either population. The data suggest that each laboratory measured the same humoral immune response and that their HPV-16 VLP ELISAs performed similarly (Pearson correlations). Interlaboratory differences, however, probably due to reagents and procedures, were considerably greater than intralaboratory day-to-day variability. Interlaboratory agreement in determining seropositivity (kappa) could be improved by sharing positive and negative serum controls and by treating marginal results as indeterminate. As part of continuing cooperation to improve interlaboratory agreement, we are preparing bulk serum control specimens to be shared and made available to interested researchers.

Fulminant course of a microinvasive vulvar carcinoma in an immunosuppressed woman

Iatrogenic immune suppression following renal transplantation is frequently associated with certain neoplasms, including vulvar carcinoma. We describe a patient with a vulvar carcinoma less than 1 mm depth of invasion and less than 3 mm superficial spread 12 years after renal transplantation. A simple vulvectomy was performed but 4 months later disease recurred in the inguinal nodes. The patient died 20 months later with progressive disease in the retroperitoneum and liver metastases.