Allelic status of chromosomes 17p, 18q, 22q [corrected] 3p and their clinical usefulness in colorectal cancer

To determine whether the allelic status of chromosomes is clinically useful in colorectal cancer, the allelic losses at chromosomes 17p, 18q, 22q and 3p and their relationships with the clinicopathological features in colorectal cancer (CRC) patients, who had undergone curative surgery without adjuvant chemotherapy, were examined.

The allelic status at 17p, 18q, 22q and 3p was analyzed by PCR-SSCP (polymerase chain reaction single-strand conformation polymorphism) in 139 CRC from patients who had undergone curative surgery between October 1994 and June 1996. The relationships between these allelic losses and the clinicopathological features were investigated.

The lymph node status was significantly associated with the allelic status of 17p, 18q and 22q. The tumor site and tumor differentiation were significantly associated with the allelic status of 18q. When patients with more than two allelic losses were defined as the high allelic loss group and those with no, or only one allelic loss were defined as the low allelic loss group, it was found that the lymph node involvement was significantly higher in the high than in the low allelic loss group. Only three out of 25 patients in the low allelic loss group had lymph node metastasis, and 15 patients in this group without lymphatic invasion had no lymph node metastasis. There was no relationship between the allelic status and survival at any stage.

The allelic status was significantly associated with lymph node metastasis. A combination of allelic status and lymphatic invasion assessment can predict the lymph node status before radical surgery.