Moreover, it was demonstrated that expression of this receptor inhibits the growth of tumor cells promoting the expression of proteins p21 and p27 and inhibiting the expression of cyclin B1 (49). treatment as by RECIST 1.1, 12 (54.5%) had partial response, 5 (22.7%) had stable disease, and 3 (13.6%) had progression. None of the patients had a complete response. Of those who had a partial response, 9 (75%) had a high or moderate degree of ER expression in tumor cells, and 3 (25%) had a low or null degree of expression. Conclusions High and moderate expression of ER group with advanced clinical stage malignant pleural mesothelioma was associated with a tendency of higher OS and better response to chemotherapy treatment resulting in longer PFS although statistical significance was not achieved. than in by macrophage activation (33) that results in increased NF-B activity, a signaling pathway that plays a role orchestrating the inflammatory response as well as cell proliferation (34). This state of inflammation has tried to be demonstrated in different ways such as the verification of the presence of antinuclear autoantibodies (35) or elevation of biomarkers such as serum mesothelin in those exposed to AG-1024 (Tyrphostin) asbestos fibers (36). MPM is hard to stage due to the lack of consensus on the staging system, however, particularly among patients that do not undergo surgery, it is a common practice to use the American Joint Committee on Cancer (AJCC) TNM (tumor, nodes, metastasis staging system) (37-39). A biopsy to have a definitive diagnosis is of high importance to begin treatment expeditiously (40-42). Recently, the role of estrogen receptor expression in different human tumors has remained controversial (43), however, in malignant mesothelial tissue there is evidence of its usefulness as a prognostic factor (44-46). Considering that this tumor is less frequent in women and that they have a more favorable prognosis (47), it may be hypothesized that development of this tumor could be related to the expression of estrogen receptors (48). A study that analyzed 78 samples of MPM tissue and 21 samples of normal pleural tissue and demonstrated that there was no expression of ER in any of the samples, either malignant or normal. On the other hand, both tissue types presented expression of ER. This same study AG-1024 (Tyrphostin) demonstrated that overexpression of this receptor is independently related with a better survival prognosis, most notably in the epithelioid histological subtype. Moreover, it was demonstrated that expression of this receptor inhibits the Rabbit polyclonal to ERO1L growth of tumor cells promoting the expression of proteins p21 and p27 and inhibiting the expression of cyclin B1 (49). It has even been possible to link the expression of ER to the cells metabolic state, where a higher lactate concentration in the intracellular space results in a greater expression of ER (50). Conversely, two studies have demonstrated that using a selective agonist of ER, in this case, a molecule known as KB9520 decreases the growth of MPM cells in both and in murine models (50,51). In addition, there is evidence that the selective agonism of this receptor could increase the sensitivity to the antitumor treatment. In one study an increased sensitivity to cisplatin was reported together with a protective effect to this cytotoxic agent in normal mesothelial cells (51-53). In a similar fashion, another study produced sensitivity to the use of the EGFR AG-1024 (Tyrphostin) tyrosine-kinase inhibitor gefitinib, which seems AG-1024 (Tyrphostin) to diminish its rate of internalization when the agonist KB9520 was added to an model (54). The aim of this study was to assess the response rate to first-line chemotherapy in malignant pleural mesothelioma with an expression of ER. Methods A retrospective study was performed at the Thoracic Oncology and Pathological Anatomy departments at INER, in Mexico City. The study design was approved by INERs Institutional Ethics Board in accordance with the Declaration of Helsinki, Fortaleza Brazil 2013 (approval document: C56-18). Patients older than 18 years old with a histopathological diagnosis of malignant pleural mesothelioma were included, diagnosed between December 2013 and June 2016, with at least one chest imaging study prior to the start of chemotherapy. Exclusion criteria were underage patients, those that underwent resection or radiotherapy with curative intent AG-1024 (Tyrphostin) prior to chemotherapy, and those without a complete medical history.