[Relationship among expression of HLA antigen, cell ploidy and metastasis in human colorectal cancer].

HLA antigen expression, cell ploidy determined by DNA content with flow cytometry, and tumor metastasis were analysed and studied in 51 cases of human colorectal cancer samples. It was observed that the pattern of HLA expression and lymph node metastasis varied significantly when the cancer cells were categorized into distinct ploidies. For tetraploid cancer cells, the percentage of positive expression of class I and II antigens were all 90.0% with no detectable metastasis. On the contrary, the expression of class I and II antigens were as low as 13.3% and 40.0% with metastasis in 26.7% of the samples from diploid group. or 20.0% and 40.0% with a metastasis percentage of 60.0% for heteroploid group. The relevant patterns for triploidy and aneuploidy were between the above three groups. The significance of the unexpected low metastasis of the tetraploid cancer cells both in clinical prognosis and mechanism studies is further discussed.