Our on-going preliminary multi-center studies indicate that in addition to lung, esophageal and gastric carcinomas, there is a high frequency of CTC subtypes with diversified CK18 expression in several types of cancer including renal cell, HCC, ovarian, colorectal, and pancreatic cancers, etc. (unpublished results). The gene discussed is KRT18; the disease is hepatocellular carcinoma.