OBJECTIVETo investigate the clinicopathological significance of p16(INK4A) expression and DNA ploidy status in HPV-negative uterine cervical cancers and their precursors.

METHODSHPV-negative cervical lesions, including 20 cases of cervicitis, 20 cases of cervical intraepithelial neoplasm (CIN), 3 cases of cervical glandular intraepithelial neoplasm (CGIN), 38 cases of invasive squamous cell carcinoma (SCCs) and 15 cases of invasive adenocarcinoma were selected and subject to screening for HPV infection by PCR method. The p16(INK4A) protein expression and DNA ploidy status were studied by immunohistochemistry and flow cytometry respectively.

RESULTSSpecific expression of p16(INK4A) was seen in both the nucleus and cytoplasm of the dysplastic and malignant cells of CIN, CGIN, cervical SCC and adenocarcinoma. In contrast, no expression was present in normal and inflammatory squamous or glandular epithelium. DNA aneuploidy was significantly more frequent in invasive SCCs and adenocarcinomas than in CIN (P < 0.01). Aneuploid was also more frequent in the lymph node positive group than lymph node negative group, although no statistic significance was found. Among the 8 cases of p16(INK4A) negative SCCs, two showed DNA aneuploidy.

CONCLUSIONSImmunohistochemical detection for p16(INK4A) can be an early diagnostic marker for HPV-negative cervical SCC and adenocarcinoma. DNA ploidy analysis may further assist the diagnosis of cervical malignancies.