Indicators
The levorotatory isomer of the aromatic amino acid tyrosine. L-tyrosine is a naturally occurring tyrosine and is synthesized in vivo from L-phenylalanine. It is considered a non-essential amino acid; however, in patients with phenylketonuria who lack phenylalanine hydroxylase and cannot convert phenylalanine into tyrosine, it is considered an essential nutrient. In vivo, tyrosine plays a role in protein synthesis and serves as a precursor for the synthesis of catecholamines, thyroxine, and melanin.
Indicators
Tumor-associated oncofetal glycoprotein 72 (TAG-72) is a high molecular weight (220-400 kD) complex expressed by a wide variety of human adenocarcinomas. This antigen is expressed by a majority of invasive ductal breast carcinomas, and most colon, pancreatic, gastric, esophageal, lung (non-small cell), ovarian and endometrial adenocarcinomas, and on normal secretory endometrium, but not on other normal tissues. It is not expressed by leukemias, lymphomas, sarcomas, mesotheliomas, melanomas or benign tumors. The monoclonal antibodies against TAG-72 have been widely employed for the immunohistochemical analysis of adenocarcinomas as well as for radioimmunoscintigraphy and radioimmunoguided surgery.
