Recently, the molecular pathologic investigation for clonality in lymphomas has been introduced and has gained a role in the diagnosis of lymphomas. In fact, the clonality test using TCRGR phenomenon has been done by Southern blot analysis (SBA) and polymerase chain reaction (PCR) for molecular pathologic diagnosis of T cell lymphomas. However, it is difficult to perform SBA with paraffin embedded specimens or with samples of small skin biopsies.

We investigated the efficacy of PCR amplification of TCR gene in paraffin em-bedded cutaneous T cell lymphomas.

Iii this study, the clonality was assessed by polymerase chain reaction (PCR) analysis of T cell receptor gamma (TCR) gene from the DNA extracts obtained from paraffin em-bedded tissues (PET) of malignant T cells, B cell lymphomas, and benign cutaneous T cell proliferative disorders. Heteroduple-x-analyses were also performed to rule out the false positives.

Among the total of 62 cases analyzed, monoclonality was observed in 4 out of 10 mycosis fungoides, 7 out of 9 cutaneous T cell lymphomas excluding mycosis fungoides, 1 out of 3 angiocentric lymphomas, 2 out of 2 lymphomatosis papulosis, 1 out of 7 large plaque parapsoriasis, and 1 out of 2 T cell lymphomas in other organs. No monoclonality was observed in 9 inflammatory cutaneous diseases, 5 small plaque parapsoriasis, 4 cutaneous B cell lymphomas, and 11 B cell lymphomas in lymph nodes.

The results suggest that the PCR method and heteroduplex analysis used in this study were not only practical but also efficacious for the diagnosis of cutaneous T cell lymphomas using tissues embedded in paraffins.