Patients whose scores on the brief fatigue inventory (BFI) increase after having received the first cycle of chemotherapy will be considered as having manifested fatigue. The patients whose fatigue won't worse following the first cycle of chemotherapy will be used as controls. We will collect blood samples of both groups before and 21 days after the start of chemotherapy. We will analyze the following biomarkers: IL2, IL10, TNF and TGFB-1 measured by amplification reaction; FSH, LH, estradiol, DHEA, DHEAS and cortisol hormones measured by chemiluminescent enzyme immunometric assay