New method to characterise and monitor skin tumour cells in CTCL patients

A new method has been developed to characterise and monitor skin resident tumour cells in CTCL patients, a Dutch study confirmed. Systemic treatment with mogamulizumab was found not to alter the phenotype of skin resident tumour cells in these patients.

Researchers from Leiden University Medical Center in the Netherlands described the new method they used as follows: With an optimised kit from Miltenyi they dissociated skin biopsies. The single-cell suspension was stained with 14 cell-surface markers and a viability stain. Stained samples were acquired with a BD Fortessa flow cytometer and manually analysed using Infinicyt^TM software. Blood was also sampled to assess the overlapping 12 surface markers with flow cytometry. In 8 out of 11 participants, a biopsy before treatment was performed and analysed, followed by biopsies at 3-17 month intervals; in 3 patients, samples were obtained during treatment with mogamulizumab.

Tumour cells were found in biopsies from 7 out of 8 untreated patients, and in follow-up biopsies in 6 patients. In the remaining 5 patients, including all 3 receiving mogamulizumab, tumour cells had disappeared. Of 15 phenotyped samples of circulating tumour cells in the skin, 12 (80%) had an unchanged immunophenotype. The other 3 had an altered CD2-, CD3- and CCR4-expression. The phenotype of the tumour cells in the skin did not change over time in any patient. In 6 out of 12 and 7 out of 12 patients treated with mogamulizumab, tumour cells were no longer detected in the skin and in the blood, respectively.

1. de Bie FJ, et al. Flow cytometry of skin biopsies in CTCL patients during mogamulizumab treatment. Abstract A-222, EORTC-CLTG 2024, 9-11 October 2024, Lausanne, Switserland.

Posted on 11 October 202411 October 2024