Breast cancer is the most common oncology disease in women and is one of the major public health issues. Worldwide, is the second leading cause of cancer death in women and cancer research is a priority in all the laboratories of the world, in terms of uncovering the appearance causes of the malignant process, understanding the mechanisms of development, but most of all, the discovery of early diagnostic methods and effective treatment. Ignorance, fear of diagnosis, lack of health education and of efficient programmes for prevention and screening could cause diagnosis of the disease to be detected in the majority of cases in advanced stages, when treatment remains only palliative and very costly, in this cases the patient's suffering being immense. In this way, regarding the clinical diagnosis in stage I mammary gland cancer, in the 496 stage I MGC patients, during the primary clinical investigation the diagnosis of stage I MGC was established only in 165 (33.3%) patients, and in 232 (46,8%) patients the diagnosis of suspicion MGC was obtained. Also, in terms of instrumental diagnosis, such as mammography, ultrasonography in mammary gland cancer stage I, it seems that in accordance with literature data the pathological process features assessment in the mammary gland is problematic especially in young age. Thus, it seems that MGC represents a polymorphic and pathogenic disease and it cannot be admitted that all subgroups of patients will obtain identical results from one tactic of treatment determined for all the patients with MGC. In this way, the concept of MGC both clinical and patho morphological, combines different cell clones depending on its microstructure and biology. As a result, the evolution of the disease, the prognosis and the effectiveness of the treatment may vary in different patients at the same stage, depending on the degree of malignancy of the tumor, its histopathological structure, the degree of expression of molecular markers identification and also immune resistance.