Tumor metabolism and prognostic role of EZH2 in non-small cell lung cancer

Epigenetic parameters—as DNA methylation and histone acetylation - play pivotal roles in carcinogenesis (1). Polycomb group (PcG) proteins are epigenetic effectors that maintain the silenced state of genes. The enhancer of zeste homolog 2 (EZH2) is one of the most important components of the polycomb repressive complex 2 (PRC2) and plays an important role in tumorigenesis and cancer progression (2). EZH2 has also been shown to be a key regulator of tumor angiogenesis (3). Overexpression of EZH2 has been associated to patients’ prognosis in various malignant tumors; on the other hand, recent studies have hypothesized that EZH2 is involved in drug resistance in ovarian cancers and its overexpression is detected in cisplatin-resistant lung cancer cells. Nevertheless, the relationship between the EZH2 expression and the development of chemotherapy resistance to NSCLC is still unclear, as well as its prognostic role (4-7).