Endocrine tumor antibodies

Antibodies to these PEMs are directed to the apical membrane portions of secretory mammary cells surrounding milk fat globules (mol wt >250 kDa). They react with a variety of epithelial tumors, including mesotheliomas. Like keratin, these antibodies are also expressed on synovial sarcomas, epithelioid sarcomas, and chordomas. They are not as reactive with as wide a variety of tumors as antikeratins. For instance, they do not react with many endocrine tumors. However, they may recognize some renal-cell carcinomas and small-cell anaplastic carcinomas... 

With the introduction and use of monoclonal antibodies, the measurement of hormones is now accurate and precise. The production of hormones in cancer involves two separate routes. First, the endocrine tissue that normally produces it can produce excess amounts of a hormone. Second, a hormone may be produced at a distant site by a non-endocrine tissue that normally does not produce the hormone. The latter condition is called ectopic syndrome. For example, the production of adrenocorticotropic hormone (ACTH) is norraotopic by the pituitary and is ectopic by the small cell of the lung. Consequently, elevation of a given hormone is not diagnostic of a specific tumor, because a hormone may be produced by a variety of cancers. 

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