Chausovsky et al., used RT-PCR to examine the usefulness of CK20 expression in CTCs in the diagnosis of metastatic lung, stomach, colon, and pancreatic cancers (Chausovsky et al., 1999), since CK20 has been shown to not be transcribed in cells of hematopoietic lineage (Burchill et al., 1995). The gene discussed is KRT20; the disease is familial pancreatic carcinoma.