Global gene expression analysis of human colorectal cancer tissue

Generally, cancer tissue is palpated as a hard mass. On the other hand, it is not clear the nature of elasticity in cancer tissue. The aim in this study is to evaluate clinical utility of measuring elastic module in colorectal cancer tissue. Using a tactile sensor, we measured the elastic module of 106 surgically resected colorectal cancer tissues. The data of the elastic module were compared with the clinicopathological findings including stromal features represented by azan and α-SMA positive area ratio in tumor area. Finally cDNA microarray profile of the tumor with high elastic module was compared with that with low elastic module Higher elastic module in tumor was associated with pathological T-, N- and M-Stage (p < 0.001, p = 0.001 and p = 0.011, respectively). Patients with high elastic module showed shorter disease free survival than patients with low elastic module. The elastic module showed strongly positive correlation with azan positive area ratio (r = 0.908) and α-SMA positive area ratio (r = 0.921). Finally, the cDNA microarray data of the tumor with high elastic module revealed distinct gene expression profile from that with low elastic module. Assessment of elasticity of colorectal cancer tissue can be available for more accurate clinical stage or prognosis estimation. Distinct phenotypical feature of the high elastic module tumor and their strong association with stromal feature seemed to be suggesting the existence of biological mechanism involved in this phenomenon, which may contribute to the future therapy. We selected four samples from the highest and the lowest EM with RIN > 6.0 measured with a 2100 Bioanalyzer (Aligent Tochnologies, Santa Clara, CA, USA) and with stage II (pTNM pathologic classification). We excluded one sample in each group because of high GAPDH.