ABSTRACT
How can the PCR product from the malignant clone be discerned from the PCR products of nonclonal T-cell after preparation of DNA from suspected CTCL skin lesions and amplification of a portion of the TCR gamma chain? Cutaneous T-cell lymphoma skin lesions contain malignant and nonmalignant cells as well as other cell types like keratinocytes and fibroblasts. The TCR gamma genes of nonlymphoid cells should not yield a PCR product, as the TCR genes are not rearranged in these cell types and the resulting PCR product would be too long to be efficiently synthesized. After gel electrophoresis on a native polyacrylamide gel, a somewhat diffuse band would be found, which consists of the TCR gamma chain products of the malignant and nonmalignant T-cells. However, it is not possible to detect a prominent band that would be diagnostic for the predominant malignant T-cell clone. Thus, an additional step is necessary for its detection and this step is the denaturation and following renaturation of the amplified double-stranded PCR product.
