Expression of the HMGI(Y) gene in human colorectal cancer

Expression of HMGI(Y), a nucleoprotein that binds to AIT rich sequences in the minor groove of the DNA helix, is observable in neoplastically transfor med cells but not in normal cells. We have analyzed HMGI(Y) expression in c olorectal cancer and evaluated its clinicopathologic significance. HMGI() m RNA was measured by CRT-PCR (competitive reverse transcription-polymerase c hain reaction). Immunohistochemical staining for HMGI(Y), p53 and Ki-67 was performed in the same colon cancer tissues, and the results in colorectal tissues were similar to those of RT-PCR. HMGI(Y) expression evidenced by RT -PCR was observed in 63 of 64 (98.4%) colorectal cancer samples, and 2 of 5 (40%) adenomatous polyps, whereas 21 normal colon samples were negative (p <0.001). High HMGI(Y) expression using CRT-PCR was found in colon cancers w ith a high Ki-67 labeling index (p<0.001). There was no significant correla tion between the levels of HMGI(Y expression and stage, tumor size, lymph n ode metastasis, histologic grade and immunohistochemical status of p53. Our results indicate that the HMGI(Y) expression may occur at an early stage o f carcinogenesis and correlate with cell proliferation. Int. J. Cancer (Pre d. Oncol.), 84:376-380, 1999. (C) 1999 Wiley-Liss, Inc.