Prognostic significance of human papillomavirus DNA in vulvar carcinoma

Does lichen sclerosus play a central role in the pathogenesis of human papillomavirus negative vulvar squamous cell carcinoma? The itch-scratch-lichen sclerosus hypothesis

In the past decade, two types of vulvar squamous cell carcinoma (SCC) have been delineated, Human papillomavirus (HPV) positive and negative. Clinicopathologic, virologic, cytomorphometric, and genetic differences support the view that these two types of carcinoma are fundamentally different and that HPV-negative carcinoma is not simply carcinoma where viral DNA has not been able to be identified. The traditional view of HPV-negative carcinoma is that it is caused by chronic tissue damage from itching and scratching. However, itching and scratching alone do not explain the close association of carcinoma with lichen sclerosus, nor the absence of such an association with other itchy conditions such as eczema or psoriasis. These observations point to a role for lichen sclerosus in the pathogenesis of vulvar carcinoma. Most observations about the etiology of lichen sclerosus can be grouped into its immunogenetic or genital predisposition, or the Köbner phenomenon. In the itch-scratch-lichen sclerosus hypothesis, lichen sclerosus is postulated to occur as a Köbner phenomenon in women with the susceptible immunophenotype who scratch because of genital irritants such as urine, vaginal secretions and smegma, and psychological factors. Lichen sclerosus, itself a very itchy condition, contributes to a vicious cycle of itching and scratching which leads to superimposed lichen simplex chronicus, squamous cell hyperplasia, and ultimately carcinoma. The itch-scratch-lichen sclerosus hypothesis reconciles the traditional itch-scratch hypothesis with the strong clinicopathologic association of lichen sclerosus with carcinoma.

The high risk human papillomaviruses and oral cancer: evidence for and against a causal relationship

Oncogenic human papillomaviruses (HPVs) have been detected in oral squamous cell carcinoma (SCC). HPV16 is the most frequently detected HPV type in oral SCC and is present in up to 22% of cases, either alone or in combination with other HPV types. HPV18 is present in up to 14% of cases. HPV16 and HPV18 are present together in approximately 6% of cases. However, HPV16 and 18 are also detected in normal oral mucosae (10% and 11% of subjects, respectively). These data suggest that high risk HPV infection may be a co-factor in oral carcinogenesis and that latent HPV infection of the oral mucosa is common. A role for HPV infection in oral carcinogenesis is supported by the ability of high risk HPVs to immortalize oral keratinocytes in vitro. Immortalization may involve (i) deactivation of pre-formed tumor-suppressor proteins by viral oncoproteins, (ii) blocking of tumor-suppressor gene transcription as a result of HPV oncogene insertion or (iii) stimulation of cellular oncogene transcription by the upstream insertion of HPV-derived transcription activating sequences. Hence, infection of oral keratinocytes with high risk HPV may be involved in the pathogenesis of some oral SCCs although the evidence implicating HPV in oral carcinogenesis is, at present, mainly circumstantial.

Epidermal growth factor receptor in vulvar malignancies and its relationship to metastasis and patient survival

OBJECTIVE

To evaluate the level of epidermal growth factor receptor (EGF-R) expression in vulvar malignancies and to determine if a correlation exists between EGF-R levels and metastasis or patient survival.

METHODS

All patients with a diagnosis of invasive squamous cell carcinoma of the vulva who were treated at our institution with a primary radical vulvectomy and inguinal lymph node dissection from 1983 to 1993 were eligible for the study. Sixty-one patients with available tissue blocks of benign vulvar epithelium, the primary malignant vulvar lesion, and groin node metastasis (when positive) were included in the study. Semiquantitative EGF-R expression was determined in a blinded fashion utilizing immunohistochemical staining of appropriate tissue samples. Survival was calculated utilizing Kaplan-Meier life table analysis based upon disease-free survival.

RESULTS

A significant increase (P < 0.001) in mean EGF-R levels was demonstrated in the primary tumor (67%) versus benign vulvar epithelium (31%). In the 14 patients with lymph node metastasis, the mean EGF-R level in the primary tumor was 65% versus 88% in the metastatic lesion (P < 0.001). The likelihood of lymph node metastasis was elevated in those patients with a benign tissue EGF-R level > or =40% (P < 0.03) and in those patients with a primary tumor EGF-R level > or =90% (P < 0.025). Life table analysis revealed a cumulative disease-free survival of 45% for all patients. Disease-free survival in those patients with EGF-R levels > or =90% in the primary tumor was 25%, contrasting with a disease-free survival of 54% in those patients with EGF-R levels <90% (P < 0.05).

CONCLUSIONS

There is a progressive increase in EGF-R expression from benign vulvar epithelium to primary malignant tissue to metastatic lesions within the same patient. Increased expression of EGF-R in the primary vulvar malignancy is significantly associated with lymph node metastasis and decreased patient survival. Increased expression of EGF-R in histologically benign vulvar epithelium has a significant association with lymph node metastasis and may predict decreased patient survival.