Histological Analysis of γδ T Lymphocytes Infiltrating Human Triple-Negative Breast Carcinomas.

Breast cancer is the leading cause of cancer death in women and the second most common cancer worldwide after lung cancer. The remarkable heterogeneity of breast cancers influences numerous diagnostic, therapeutic, and prognostic factors. Triple-negative breast carcinomas (TNBCs) lack expression of HER2 and the estrogen and progesterone receptors and often contain lymphocytic infiltrates. Most of TNBCs are invasive ductal carcinomas (IDCs) with poor prognosis, whereas prognostically more favorable subtypes such as medullary breast carcinomas (MBCs) are somewhat less frequent. Infiltrating T-cells have been associated with an improved clinical outcome in TNBCs. The prognostic role of γδ T-cells within CD3(+) tumor-infiltrating T lymphocytes remains unclear. We analyzed 26 TNBCs, 14 IDCs, and 12 MBCs, using immunohistochemistry for the quantity and patterns of γδ T-cell infiltrates within the tumor microenvironment. In both types of TNBCs, we found higher numbers of γδ T-cells in comparison with normal breast tissues and fibroadenomas. The numbers of infiltrating γδ T-cells were higher in MBCs than in IDCs. γδ T-cells in MBCs were frequently located in direct contact with tumor cells, within the tumor and at its invasive border. In contrast, most γδ T-cells in IDCs were found in clusters within the tumor stroma. These findings could be associated with the fact that the patient's prognosis in MBCs is better than that in IDCs. Further studies to characterize these γδ T-cells at the molecular and functional level are in progress.

Detection of MYD88 L265P mutations in formalin-fixed and decalcified BM biopsies from patients with lymphoplasmacytic lymphoma.

The diagnosis of bone marrow (BM) infiltration by Waldenström macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) poses a diagnostic challenge in hematopathology. No definitive morphology or immunophenotype is able to distinguish between infiltration of paraffin-embedded BM sections by WM/LPL and other indolent lymphomas, in particular those of the splenic marginal zone (SMZL) which may also show plasmacytic maturation. An oncogenic gain-of-function mutation (L265P) in the human MYD88 gene has been found to be present in most cases of WM/LPL, yet is absent in most other cases of B-cell chronic lymphoproliferative disorders (LPD), including SMZL. Here, we compare two newly developed diagnostic protocols for detection of this mutation in paraffin-embedded archival tissues which are particularly applicable to decalcified BM biopsies. Sanger sequencing can easily detect levels of BM infiltration above 15% by WM lymphoplasmacytic cells, while the allele-specific PCR can detect the L265P mutation in BM infiltrations below 1% of lymphoma cells. We show that these methods are easily applicable to archival BM specimens and markedly improve diagnostic accuracy of BM infiltrations by indolent B-cell lymphomas.