Diagnosis of cancer is enormous challenge for medicine. The detection of cancer is based of use a multiple analytical techniques (morphometric, biochemical, cytogenetic, molecular and morphologic), also very helpful are imaginig methods. Furthermore important role in diagnosis of cancer play tumor makrers. In clinical practice titer of biochemical markers are subject to the respective predictive values​​, sensitivity and specificity. Until now failed to define the substance, which could be considered as the ideal biochemical marker. This study shows the analyze recent literature data and recommendations of international organizations – American Society of Clinical Oncology (ASCO) and European Group on Tumor Markers (EGTM) for the markers used in the diagnosis of breast and ovarian cancer. The article describes crucial macromolecular substances to be used in the medical practice respectively in breast cancer: CEA, CA 15.3, CA 27.29 and ovarian cancer: CA 125, mesothelin, B7-H4 and CG.

Key words: tumor markers, predictive value of tests, breast cancer, ovarian cancer, algorithm ROMA.