Abstract
Using DNA from formalin-fixed paraffin-embedded tissue of a patient with mycosis fungoides, a highly specific and sensitive molecular probe for the malignant lymphoid cells of this patient was developed. Polymerase chain reaction (PCR) was used to selectively amplify the region of the rearrangement of TCR-γ genes. Randomly inserted nucleotides between rearranged segments (N-region) were used as a specific marker for the malignant lymphoid clone of this patient. Clonal cells in paraffin-embedded tissue of previous and later biopsies were detected. This technique provides a new and unique tool for retrospective detection of early evolving cutaneous lymphoma, as well as for detection of minimal residual and systemic disease.