TY - JOUR

T1 - Clonotypic diversity of the T-cell receptor corroborates the immature precursor origin of cutaneous T-cell lymphoma

AU - Hamrouni, Abdelbasset

AU - Fogh, Hanne

AU - Zak, Zoulika

AU - Dum, Niels

AU - Gniadecki, Robert

PY - 2019

Y1 - 2019

N2 - Purpose: Mycosis fungoides is one of the most common types of extranodal T-cell lymphomas, considered to be caused by malignant transformation of the mature T cells residing in the skin. However, some clinical observations such as the multifocal distribution of mycosis fungoides lesions or patterns of relapse after radiotherapy are not readily explainable by the mature T-cell origin theory. Experimental Design: We have performed a detailed analysis of T-cell receptor (TCR) rearrangements in single malignant cells and in biopsies from mycosis fungoides tumors composed of >80% of malignant cells using next-generation sequencing (NGS) to pinpoint the relationship between neoplastic cells in mycosis fungoides. We have also aimed to detect malignant, circulating T-cell by whole blood TCR sequencing. Results: We found a substantial clonal heterogeneity in the mycosis fungoides samples with regards to TCR, and we demonstrated that lymphoma cells harboring identical TCRg sequences may harbor different TCRa and b sequences. Lack of absolute TCRa, -b, -g monoclonality was further confirmed by TCR amplification and sequencing from microdissected lymphoma cells. We have also found the TCR rearrangements characteristic for lymphoma cells in patients' peripheral blood despite the lack of leukemic blood involvement; however, the circulating TCRg clonotype did not always represent the dominant cutaneous clonotype. Conclusions: These findings can be explained by a model where malignant transformation takes place during early T-cell development giving rise to circulating premalignant clones, which home to the skin producing clinically apparent lesions of cutaneous lymphoma. Therapeutic strategies in T-cell lymphoma should therefore target those early lymphoma precursor cells.

AB - Purpose: Mycosis fungoides is one of the most common types of extranodal T-cell lymphomas, considered to be caused by malignant transformation of the mature T cells residing in the skin. However, some clinical observations such as the multifocal distribution of mycosis fungoides lesions or patterns of relapse after radiotherapy are not readily explainable by the mature T-cell origin theory. Experimental Design: We have performed a detailed analysis of T-cell receptor (TCR) rearrangements in single malignant cells and in biopsies from mycosis fungoides tumors composed of >80% of malignant cells using next-generation sequencing (NGS) to pinpoint the relationship between neoplastic cells in mycosis fungoides. We have also aimed to detect malignant, circulating T-cell by whole blood TCR sequencing. Results: We found a substantial clonal heterogeneity in the mycosis fungoides samples with regards to TCR, and we demonstrated that lymphoma cells harboring identical TCRg sequences may harbor different TCRa and b sequences. Lack of absolute TCRa, -b, -g monoclonality was further confirmed by TCR amplification and sequencing from microdissected lymphoma cells. We have also found the TCR rearrangements characteristic for lymphoma cells in patients' peripheral blood despite the lack of leukemic blood involvement; however, the circulating TCRg clonotype did not always represent the dominant cutaneous clonotype. Conclusions: These findings can be explained by a model where malignant transformation takes place during early T-cell development giving rise to circulating premalignant clones, which home to the skin producing clinically apparent lesions of cutaneous lymphoma. Therapeutic strategies in T-cell lymphoma should therefore target those early lymphoma precursor cells.

U2 - 10.1158/1078-0432.CCR-18-4099

DO - 10.1158/1078-0432.CCR-18-4099

M3 - Journal article

C2 - 30808775

AN - SCOPUS:85065766358

VL - 25

SP - 3104

EP - 3114

JO - Clinical Cancer Research

JF - Clinical Cancer Research

SN - 1078-0432

IS - 10

ER -