Alteration of X and Y chromosomes in human esophageal squamous cell carcinoma

The incidence of human esophageal squamous cell carcinoma in males is well- known to be higher than in females and its biological action in male patien ts is generally much more aggressive than that of the female. Recently aber rations and/or other abnormalities of the sex chromosomes, especially the Y chromosome have been postulated to be involved in some of the differences in the incidence and/or biological action of human malignancies between mal e and female patients. Therefore in this study, we examined abnormalities o f the sex chromosomes in cell smears obtained from 30 male patients diagnos ed with esophageal squamous cell carcinoma. In addition, TE series cell lin es, derived from esophageal squamous cell carcinomas, were studied for sex chromosome abnormalities by utilizing a simultaneous double color fluoresce nt in situ hybridization (FISH) and these findings were correlated with,var ious clinicopathological parameters in order to examine its likely biologic al significance. In esophageal squamous cell carcinoma, Y chromosome loss w as detected in all cases studied (1.6-86.9%, mean 22.98 +/- 22.04%), but th e loss of the X chromosome was encountered in only 6 of the cases (7.1-40.6 %, mean 15.90 +/- 12.46%). There was no significant association between the rate of Y chromosome loss in carcinoma cells and any of the clinicopatholo gical parameters examined including age and stage of the cancer: Lass of th e Y chromosome was observed in only two cases of adjacent non-pathological esophageal squamous cell epithelium. Among the TE series examined, the cell lines derived from male patients demonstrated loss of the Y chromosome in all cell lines (1.4-92.9%, mean 44.92 +/- 42.55%), but the great majority o f cell lines derived fr om female patients were associated with the karyoty pe of XX. These results indicated that the loss of the Y chromosome is asso ciated with the malignant phenotype in human esophageal squamous epithelium , brit possibly not with biological behavior. These results also suggested that at least one X chromosome is indispensable for the survival of esophag eal squamous cell carcinoma.