Effects of LMP 1 expression on neoplastic cell proliferation and apoptosis in nasopharyngeal carcinoma
LI Zhi, ZONG Yongsheng. Department of Pathology, Sun Yat sen University of Medical Sciences, Guangzhou 510089
Objective To investigate the effects of LMP 1 expression on neoplastic cell proliferation and apoptosis in untreated nasopharyngeal carcinoma (NPC). Methods Biopsies from 55 untreated NPC cases were collected. EBERs was detected by in situ hybridization. PCNA, LMP 1 and bcl 2 were detected by immunohistochemistry method. Cell apoptosis was demonstrated by TUNEL (TdT mediated dUTP x nick end labeling) kit. Results (1) The positive LMP ① expression rate was 27/55 (49.1%). The median PI (PCNA Index) of LMP 1 positive cases (90.0%) was higher than that of LMP 1 negative cases (80.0%) and the p value was less than 0.05 by rank sum (rs) test. (2) The median TI (TUNEL Index) of LMP 1 positive cases (16.2 per high power field) was also higher than that of LMP 1 negative cases (10.4 per high power field) and the p value was less than 0.05 by rs test. (3) As for the bcl 2 expression percentages, no correlation was found between LMP 1 positive and negative cases. (4) A positive rank correlation existed between PI and TI (rs=0.368 1, P 0.01), but no correlation was found between TI and bcl 2 expression percentage. Conclusions (1) NPC with LMP 1 expression have higher levels of PI, maybe resulting from the promotional effect of LMP 1 on cell proliferation. (2) NPC with LMP 1 expression also have a higher level of TI, indicating that LMP 1 can induce cell apoptosis, which could not be blocked by bcl 2 expression. The authors suggest that LMP 1 expression may exert a dual action on neoplastic cell proliferation and apoptosis in untreated nasopharyngeal carcinoma.