GSTM1 and anemia (phenotype): At this regard it should be specified that cancer patients with anemia should be sorted into two main categories: those with normal Hb values before starting medical treatment (often patients with limited, locally advanced resectable disease and candidate to undergo adjuvant cancer therapy) for whom anemia must be interpreted as a specific treatment-related toxicity (chemotherapy-induced anemia); and those with diagnosis of anemia preceding antineoplastic treatment (often receiving chemotherapy for advanced cancers).