Preliminary assessment of the diagnostic accuracy of cutaneous T-cell lymphoma through deep sequencing of T-cell receptor gamma gene.

Abstract

The diagnostic challenges in early mycosis fungoides (MF) and other cutaneous T-cell lymphomas (CTCL) persist despite advancements in molecular methods. The study aims to provide a preliminary assessment of next-generation sequencing in analyzing T-cell receptor gamma (TRG) sequences for distinguishing CTCL from benign inflammatory disorders. Skin samples from CTCL and benign inflammatory skin disorders proven clinicopathologically were assessed for TRG by NGS. Our study analyzed skin samples from a total of 36 subjects, comprising 22 cases of CTCL, including 14 MF and 8 other CTCLs, alongside 14 cases of benign inflammatory skin disorders. According to the LymphoTrack criteria, monoclonality was detected in 75.0 % of the overall 24 CTCL patients. Specifically, in MF cases, 10 out of 14 were identified as monoclonality, with all four non-monoclonal cases being in the patch stage. For the other CTCL, 6 out of 8 cases displayed monoclonality. Among the overall 22 CTCL patients, 11 had multiple biopsies, with 9 displaying the same dominant clone across different sites. Among the 14 benign cases, only the case with erythrodermic psoriasis exhibited monoclonality. Our decision tree analysis suggests that a high frequency of the most abundant clone, its ratio to the third most abundant clone, and TRG V-I segment usage are effective markers aiding in diagnosing CTCL. Combination of the clone frequencies, and TRG V segment usage may enhance diagnosis for MF and other CTCLs, aiding in differentiating them from benign conditions. However, molecular diagnosis for patch-stage MF remains challenging.