[In situ PCR in the diagnosis of acute leukemia]

Cytomorphologic and cytochemical bone marrow analysis is essential in the diagnosis of acute leukemia. Immunophenotyping and conventional cytogenetics, just as fluorescent in situ hybridization (FISH) are other diagnostic procedures, as well as genome analysis by PCR (polymerase chain reaction). PCR is inevitable in searching for minimal residual disease, because it may detect very small amount of malignant hematopoietic cells even when a patient is in complete remission (less than 5% malignant cells in bone marrow and disappearance from peripheral blood) which helps better monitoring of patients. By in situ hybridization (ISH) it is possible to associate specific cell type with genome alteration, but the method is not sensitive enough. By combining ISH and PCR a novel technique with increased sensitivity was developed, PCR in situ, which enables nucleic acid amplification in an intact cell. In this case report we present two patients whose bone marrow aspirates were analyzed also by PCR in situ.