人乳头状瘤病毒阴性的宫颈癌及其癌前病变中p16^(INK4A)蛋白表达和DNA倍体分析

Study of p16(INK4A) expression and DNA ploidy in HPV-negative cervical cancers and precursors

目的探讨人乳头状瘤病毒(HPV)感染阴性的宫颈癌及其癌前病变中p16INK4A蛋白表达和DNA倍体分析的临床病理学意义。方法应用PCR方法筛查出HPV感染阴性的20例慢性宫颈炎、20例宫颈上皮内瘤变(CIN)、3例宫颈腺上皮内瘤变(CGIN)、38例浸润性鳞状细胞癌(鳞癌)和15例浸润性腺癌作为研究对象。应用免疫组织化学(LSAB)染色方法检测p16INK4A蛋白在这些病变组织中的表达,并结合流式细胞仪DNA倍体分析探讨HPV阴性的宫颈癌的早期诊断和预后判定。结果p16INK4A蛋白特异性地表达在CIN和CGIN病变、鳞癌以及腺癌细胞的胞核和胞质中,而在正常鳞状上皮和腺上皮中没有任何阳性表达信号。另外,DNA异倍体在浸润性鳞癌和腺癌中的表达率明显高于CIN病变组(P<0．01)。在有淋巴结转移的浸润癌中DNA异倍体存在的百分率高于无淋巴结转移组,但尚未发现差异有统计学意义。在8例p16INK4A表达阴性的浸润性鳞癌中有2例表现为DNA异倍体。结论p16INK4A蛋白检测可以作为HPV感染阴性的宫颈鳞癌及腺癌的早期诊断指标,结合DNA倍体分析将对宫颈恶性肿瘤的诊断有重要的辅助意义。

Objective To investigate the clinicopathological significance of p16^INK4A expression and DNA ploidy status in HPV-negative uterine cervical cancers and their precursors. Methods HPV-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. Results Specific 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. Conclusions Immunohistochemical 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.