Researchers in New South Wales, Australia may have found one of the reasons for survival differences in men and women with malignant peritoneal mesothelioma. The key may be in their hormones.
The sex hormone estradiol is produced by the ovaries and the adrenal gland in women and is an active metabolic product of testosterone (though in much lower levels) in men. The most important form of estrogen in the body, estradiol has been shown to be involved in cellular proliferation of a number of cancers and acts mainly through estrogen receptors.
Peritoneal mesothelioma is a cancer than spreads across the thin membrane that lines the wall of the abdomen. Using immunohistochemical testing, the Australian team measured estrogen receptors in 42 patients with peritoneal mesothelioma. Thirty-three of the patients tested were found to have a certain type of estrogen receptor (ER-â) in the nucleus of cells. Nine patients were found to have ER-â in their cellular cytoplasm, the gel-like substance inside cells between the cell wall and the nucleus.
When these estrogen receptor levels were compared with mesothelioma outcomes, the study found that both the presence and location of estrogen receptors appeared to play a role. The authors write, “The absence of ER-â (nuclear) and the presence of ER-â (cytoplasm) were found to be independent predictive factors for poor disease outcome.” Previous studies have suggested that estrogen receptors are also prognostic factors in non-small cell lung cancer.
Formulating a reliable mesothelioma prognosis is more than just a way to predict how long a patient may live. In a disease like mesothelioma, which progresses quickly and tends to be resistant to conventional therapy, prognostic factors can impact a patient’s treatment plan. Although many factors influence mesothelioma prognosis, including age, gender, cancer stage, histology, and a number of different biomarkers, this new study suggests that the presence or absence of estrogen receptors may be one more way to help individualize treatment and improve outcomes.
Because the Australian study on mesothelioma and estrogen receptors is small, the authors say that their findings will need to be supported by larger studies before the information can be incorporated into clinical practice in the treatment of mesothelioma.
Kawai, H et al, “Estrogen receptor alpha and beta are prognostic factors in non-small cell lung cancer”, July 15, 2005, Clinical Cancer Research, pp. 5084-5089.