Detecting disseminated solid tumor cells in hematopoietic samples: methodological aspects.

Detection of tumor cell dissemination in solid tumor patients recently became essential to determine the prognosis of the disease and to monitor response to the therapy. Accurate detection of disseminated tumor cells in hematological samples requires tumor-specific target molecules, which allow sensitive and specific assays and, further, enable the quantification of tumor cells. Currently, numerous applications are in use, including immunological and molecular biological approaches. Theoretically, both ways are sensitive enough to detect less than one tumor cell in 1 million hematopoietic cells. With the improved sensitivity, however, the likelihood that unspecific events will be amplified is also increased. Moreover, biological and analytical variables may fundamentally influence the findings in a particular case. Basic methods, significant pitfalls and the most recent developments in this field are discussed in this overview.