Human papillomavirus and endocervical adenocarcinoma

Prevalence of human papillomavirus DNA in different histological subtypes of cervical adenocarcinoma

The prevalence of human papilloma virus (HPV) DNA in different histological subtypes of cervical adenocarcinoma and related tumors was examined using formalin-fixed, paraffin-embedded tissue samples from 105 primary cervical adenocarcinomas and adenosquamous carcinomas. Broad-spectrum HPV DNA amplification and genotyping was performed with the SPF10 primer set and line probe assay (LiPA), respectively. HPV DNA was detected in 82 of 90 (91%) mucinous adenocarcinomas, encompassing endocervical, intestinal, and endometrioid histological subtypes, and in nine of nine adenosquamous tumors (100%). HPV DNA was not detected in any nonmucinous adenocarcinomas including clear cell, serous, and mesonephric carcinomas (0/6). The most common viral types detected in adenocarcinoma were HPV 16 (50%) and HPV 18 (40%), followed by HPV 45 (10%), HPV52 (2%), and HPV 35 (1%). Multiple HPV types were detected in 9.7% of the cases. In conclusion, mucinous adenocarcinomas and adenosquamous carcinomas of the cervix demonstrate a very high prevalence of HPV DNA, similar to that reported for cervical squamous cell carcinoma. Only rare histological variants of cervical adenocarcinoma seem unrelated to HPV infection.

Molecular events in uterine cervical cancer

OBJECTIVE

To review the literature regarding the molecular events which occur in the development of uterine cervical cancer, with particular reference to human papillomavirus (HPV) infection.

METHODOLOGY

Bibliographic searches of Medline and the ISI citation databases using appropriate keywords, including the following: papillomavirus, cervix, pathology, cyclin, chromosome, heterozygosity, telomerase, smoking, hormones, HLA, immune response, HIV, HSV, EBV.

CONCLUSIONS

It has become clear that most cervical neoplasia, whether intraepithelial or invasive, is attributable in part to HPV infection. However, HPV infection alone is not sufficient, and, in a small proportion of cases, may not be necessary for malignant transformation. There is increasing evidence that HPV gene products interfere with cell cycle control leading to secondary accumulation of small and large scale genetic abnormalities. This may explain the association of viral persistence with lesion progression but, in many patients, secondary factors, such as smoking and immune response, are clearly important. However, the mechanisms involved in the interaction between HPV and host factors are poorly understood.

Prevalence of human papillomavirus DNA in cervical tissue. Retrospective analysis of 855 cervical biopsies

The histopathologic features of 855 cervical biopsies were correlated with the presence of human papillomavirus DNA using in situ hybridization (ISH) with biotin labeled type specific probes for Human Papilloma Virus (HPV) types 6, 11, 16, 18, 31, 33 and 51. HPV-DNA was found in 18% (13/72) of cervical intraepithelial neoplasia I (CIN I), 30% (35/115) of CIN II, 28% (57(206) of CIN III, in 84% (21/25) of flat condyloma and in 13% (15/112) of normal cervical tissue. HPV DNA was detectable in 11% (5/46) of cervical adenocarcinoma and in 21% (59/279) of squamous cell carcinoma (SCC) of the cervix. High risk HPV types were identified more often than low risk HPV types in CIN I, CIN II, CIN III and SCC. HPV type 16/18 predominates over HPV types 31/33/51 in CIN I, flat condyloma and in SCC. The prevalence of HPV was strongly associated with the grade of differentiation of SCC. It was identified in 59% (23/39) of well differentiated SCC, in 18% (25/142) of moderately differentiated and in 11% (11/98) of poorly differentiated SCC.

The epidemiology of cervical carcinogenesis

Epidemiologic and laboratory data suggest that cervical cancer typically arises from a series of causal steps. Each step can be studied separately in the hope of better etiologic understanding and improved cancer prevention. The earliest identified etiologic step is infection of young women with specific types of venereally transmissible human papillomaviruses (HPVs). Cervical HPV infections often lead to low grade squamous intraepithelial lesions (mildly abnormal Pap smears). Human papillomavirus infections and their associated lesions are extremely common among young, sexually active women. The infections typically resolve spontaneously even at the molecular level within months to a few years. Uncommonly, HPV infections and/or low grade lesions persist and progress to high grade lesions. The risk factors for progression are mainly unknown but include HPV type and intensity, cell-mediated immunity, and reproductive factors. Nutritional factors or co-infection with other pathogens may also be involved at this apparently critical etiologic step between common low grade and uncommon high grade intraepithelial lesions. Except for advancing age, no epidemiologic risk factors have been found for the next step between high grade intraepithelial lesions and invasive cancer. At the molecular level, invasion is associated with integration of viral DNA. Based on worldwide research, the steps in cervical carcinogenesis appear to be fundamentally the same everywhere, with a central role for HPV infection. The importance of etiologic cofactors like smoking, however, may vary by region.