Variant gamma-glutamyltransferase in colorectal carcinoma and liver metastasis. A case study

Two variant forms of gamma-glutamyltransferase have recently been demonstrated in colorectal carcinoma. They differed from the enzyme in normal colon mucosa by altered sialic acid content, and Concanavalin A affinity. A search for a variant gamma-glutamyltransferase was undertaken in liver metastasis from one patient with colorectal carcinoma. The enzyme in the metastatic tissue was clearly different from the normal liver enzyme and apparently identical to the variant enzyme in the primary tumor. Thus, the variant form appears to be related to the neoplastic transformation. However, as antigenic properties of the metastatic enzyme were apparently identical to those of the normal liver enzyme, they will not be true isoenzymes.