Prolactin has, for long, been associated with
galactorrhea and
infertility in women while its role in men is largely unknown. Recently, expression of
prolactin in various other tissues like the breast, prostate, decidua, and the brain has been recognized. This has led to evaluation of paracrine and autocrine actions of
prolactin at these tissues and a possible role in development of various
cancers. Increased expression of
PRL receptors has also been implicated in
carcinogenesis.
Breast cancer has the strongest association with increased
prolactin and
prolactin receptor levels.
Prostate cancer also has reported significant association, while the role of
prolactin in colorectal, gynecological, laryngeal, and
hepatocellular cancers is more tenuous.
Prolactin/
prolactin receptor pathway has also been implicated in development of resistance to
chemotherapy. Thus, the effects of this pathway in
carcinogenesis seem widespread. At the same time, they also offer an exciting new approach to hormonal manipulation of
cancers, especially the treatment-resistant
cancers.