Colorectal and breast cancer are the most common cancer types worldwide and they continue to be a serious public health problem. Early detection and diagnosis are of great importance in cancer management. At present, diagnostic blood tests are based on detection of tumor-associated markers such as CEA, PSA, AFP, and others. The lack of sensitivity and specificity of these markers prevents their general use in cancer screening of an average risk population. Therefore, new cancer biomarkers or better screening methods are necessary to improve the diagnostics of the disease. This work was directed to establishment of a diagnostic, ELISA-based test to identify and validate new serum markers, such as ecPKA and NNMT, potential candidates for detection of early human breast and colorectal neoplasm. This specific auto-antibody ELISA is thought to identify the cancer antigens by detecting the presence of auto-antibodies against the tumor proteins in human serum. In conclusion it has been showed that anti-ecPKA auto-antibody ELISA is functional and easy to perform and it could have a promising role in early diagnostic/prognostic of other cancer types.