Nesfatin-1 is a peptide of 82 amino acids, an adipokine, it is a derivative of NUCB2 (nucleobindin 2). Due to the identical localization of the two peptides in the tissues of the host, they were often evaluated together, as the NUCB2/Nesfatin-1 complex. Nesfatin-1 is associated with the control of mechanisms linked to generative functions and obesity. A relationship has been demonstrated between concentrations of nesfatin-1 and type II obesity. The relationship between obesity and the development of malignant tumours in various locations has been confirmed. Moreover, in obese patients, due to insulin resistance, secondary hyperinsulinaemia exists as well as an increased secretion of IGF. Both insulin and IGF activate a number of signalling pathways which stimulate cell proliferation and inhibit apoptosis, in this way promoting the development of tumours, including endometrial cancer. In studies on endometrial cancer (on cancer tissues obtained in surgery and cell lines of the cancer) the immunoreactivity of NUCB2 was demonstrated to be linked to the Ki-67 proliferative index and the clinical course of the disease. The immunoreactivity of NUCB2 manifested a correlation with an increased risk of relapse and a less advantageous clinical course PFS (progression-free survival) and total survival. Nesfatin-1 was found to promote proliferation and migration of the established endometrial cancer cell lines, Ishikawa and Savano. On the other hand, an inverse effect of nesfatin-1 was documented in vitro tests on cell lines of ovarian cancer, HO-8910. An inhibitory effect of nesfatin-1 was documented on the proliferation of the cells due to induction of apoptosis. Studies into the NUCB2/Nesfatin-1 complex seem promising in both types of cancer, endometrial and ovarian, particularly since in literature on the subject the biomarkers are considered to reflect clinical course and to represent respective therapeutic targets.