[Telomere length and DCC gene mRNA expression of human large intestine cancers]

To evaluate the role of telomere and DCC in tumor transformation and progression.

Telomere length and DCC gene mRNA expression were examined by southern blot hybridization and RT-PCR analysis in 46 adenomas of large intestine, 62 cancers of large intestine and corresponding normal mucosa.

Shortening of the telomere was present in the tissues of 41.3% of the adenomas and 53.2% of the cancers, and their average TRF lengths were significantly shorter than those of corresponding normal mucosa(P<0.05, P<0.01), whereas the telomere elongation was only detected in 4.4% and 6.5% of the adenomas and cancers respectively. In addition, the average telomere length in colon carcinomas was also shorter than that in rectal carcinomas. Moreover, the average telomere lengths of the colorectal cancer mucosa became shorter with age. The rates of DCC mRNA expression deletion were 34.8% and 62.9% in the tissues of adenomas and cancers respectively. The DCC mRNA expression deletion occurred more frequently in poorly differentiated and Dukes C, D carcinomas than in well-differentiated and Dukes A, B carcinomas (P<0.05, P<0.01). However, no significant correlation was found between the length of telomere and the deletion of DCC mRNA expression in the cancers of large intestine.

The telomere shortening and DCC mRNA deletion may represent the biologic behavior of transformation and development of the large intestine cancers.