Natural killer (NK) cells are characterized by a CD3-CD16+ CD56+ immunophenotype and have a central role in the innate immune system. They are defined by their capacity to kill certain tumour-target cells or virus infected cells without prior sensitization or MHC-restriction.The activity of the NK cells is determined by the balance between activation and inhibitory receptor molecules expressed on the surface of NK cells. However, several cytokines and chemokines can significantly modulate their activity, inducing increase of NK cell activity. Immunomodulation mediated by NK cells is very important mechanism in tumour immunity, as well as in other immunodepressions of the immune system. In this study, we summarize the role of several cytokines, including IFN, IL-1, IL-2, IL-4, IL-7, IL-12 and IL-17, on NK cell function. The NK cells, after activation, depending on cytokine environment, can differentiate into NK1 cells that produce Th1 cytokine type (IFN-gamma, IL-2, IL-12) or NK2 cells that produce Th2 type cytokines, enhance exocytosis and release of previously formed molecules from NK cells (granzyme, perforin). We also describe that the release of cytokines and mediators show local or distance effects, or induce apoptosis (mostly by secreted TNF-alpha) after binding appropriated killer cell receptors from TNF receptor superfamily.

Breast cancer is really one from tumor with highest mortality in this country as well as in the word. For early detection of the loco-regional breast cancer and disease confirmation, many diagnostic procedures were recommended with aims to help in decision for surgery treatment. This comparative study reported data by clinical analyses, ultra-sonography, mammography and histological findings obtained after ex tempore biopsy, in 59 women with breast cancer aged from 16 to 69. The highest incidence of cancer was obtained in women over 61 years of age, although high rate of breast cancer was found in aging between 21 to 50 years. The fibroadenoma were founded in 40.68%, while malignant carcinoma ductale in 13.55% of all cases. Correlation between applied analyses for fibroadenoma was found in 86.05% cases, while in malignant lesions this percentage was highest (93.33%). Apart of these methods applied for early diagnosis in general hospital and obtained statistical significance in diagnosis, new techniques based on molecular level (hormone receptor status) must be used.