Molecular detection of minimal residual disease in colorectal and breast cancer

Recent developments in the field of molecular biology enable us to detect t umour cells at a submicroscopical level. In colorectal and breast cancer th e most important prognostic factor is dissemination of malignant cells to l ocoregional lymph nodes. An important issue is whether molecular 'super'-st aging augments the accuracy by which the prognosis of individual patients c an be assessed. Over the past few years numerous studies have reported the use of different PCR-based techniques in various types of cancer. The repor ted incidence of micrometastases and specificity of different assays varies tremendously. This clearly indicates the need for uniformity in protocols, For colorectal cancer the use of molecular techniques may improve staging and guide clinical decisions. For breast cancer there is still need to prov e the clinical implication of finding occult metastatic disease. Neverthele ss, PCR-based techniques are a powerful tool in the staging of common solid tumours and are likely to find their way into the daily practice of diagno stic histopathologists in the near future.