The Diverse Roles of γδ T Cells in Cancer: From Rapid Immunity to Aggressive Lymphoma

γδ T cells are unique players in shaping immune responses, lying at the intersection between innate and adaptive immunity. Unlike conventional αβ T cells, γδ T cells largely populate non-lymphoid peripheral tissues, demonstrating tissue specificity, and they respond to ligands in an MHC-independent manner. γδ T cells display rapid activation and effector functions, with a capacity for cytotoxic anti-tumour responses and production of inflammatory cytokines such as IFN-γ or IL-17. Their rapid cytotoxic nature makes them attractive cells for use in anti-cancer immunotherapies. However, upon transformation, γδ T cells can give rise to highly aggressive lymphomas. These rare malignancies often display poor patient survival, and no curative therapies exist. In this review, we discuss the diverse roles of γδ T cells in immune surveillance and response, with a particular focus on cancer immunity. We summarise the intriguing dichotomy between pro- and anti-tumour functions of γδ T cells in solid and haematological cancers, highlighting the key subsets involved. Finally, we discuss potential drivers of γδ T-cell transformation, summarising the main γδ T-cell lymphoma/leukaemia entities, their clinical features, recent advances in mapping their molecular and genomic landscapes, current treatment strategies and potential future targeting options.

Late non-neoplastic events in patients with aggressive non-Hodgkin's lymphoma in four randomized European Organisation for Research and Treatment of Cancer trials

BACKGROUND

A significant proportion of patients with aggressive non-Hodgkin's lymphoma (NHL) become long-term survivors. A European Organisation for Research and Treatment of Cancer database of patients with aggressive NHL, consistently treated with doxorubicin-based chemotherapy since 1980, afforded the possibility to explore late complications in this patient group.

PATIENTS AND METHODS

Of 951 randomized patients, complete data on late complications could be collected in 757 patients who were alive > or = 2 years after the start of therapy and were seen at yearly follow-ups (median follow-up, 9.4 years; range, 2.1-20.4 years). We computed cumulative incidences of late events in a competing risk model by Gray (death being the competing event) to avoid bias caused by the high percentage of NHL-related deaths. Risk factors were estimated in a Cox proportional-hazards model and also evaluated with the Gray test.

RESULTS

Late non-neoplastic events were found in 46% of the 757 patients. At 15 years, the cumulative incidences of cardiac disease and infertility were 20% and 29%, respectively. Renal insufficiency (11%), acquired hypertension (8%), and disabling neuropathy (13%) were also frequent. Salvage treatment was a risk factor in most cases. Smoking, age > 50 years during treatment, and preexistent hypertension were the main risk factors for cardiovascular disease. In-field radiation therapy (RT) was related to hypothyroidism, lung fibrosis, hypertension, gastrointestinal toxicity, and renal insufficiency but not to cardiovascular events. Autologous stem cell transplantation and cisplatin- and MOPP (mechlorethamine/vincristine/procarbazine/prednisone)-containing therapies were associated with infertility and renal insufficiency.

CONCLUSION

Altogether, almost half the patients with aggressive NHL experienced events addressed as late non-neoplastic complications. Salvage therapy, smoking, age > 50 years, and in-field RT are important risk factors.

Long-term efficacy of the CHVmP/BV regimen used for aggressive non-Hodgkin’s lymphoma in three randomised EORTC trials

We analysed data from 936 newly-diagnosed patients with advanced, aggressive non-Hodgkin's lymphoma (NHL) treated in three randomised European Organisation for Research and Treatment of Cancer (EORTC) trials performed between 1980 and 1999 (median follow-up of 8.7 (0.2-20.4) years). The CHOP-like regimen CHVmP/BV (cyclophosphamide, doxorubicin, teniposide and prednisone with bleomycin and vincristine at mid-interval), was compared with CHVmP (CHVmP/BV without bleomycin and vincristine), ProMACE-MOPP (methotrexate, doxorubicin, cyclophosphamide, etoposide, mechlorethamide, vincristine, procarbazine and prednisone) and CHVmp/BV with additional, autologous stem-cell transplantation, respectively. Overall, treatment with CHVmP/BV resulted in a better long-term outcome with 63% complete responses being observed and an overall survival (OS) of 59 and 43% at 5 and 10 years, respectively. Remarkably, OS after CHVmP/BV improved across the trials, even after stratifying for the International Prognostic Index (IPI). This finding could not be directly related to better salvage treatments during the last decade. Selection bias appears to be responsible: stepwise corrections for small differences in inclusion criteria eliminated the difference in OS, especially when histological subgroups were studied. This systemic review underlines the difficulties encountered in retrospective sub-set analyses and the biases that can be introduced when recent studies are compared with older ones.

CHOP versus MACOP-B in aggressive lymphoma--a Nordic Lymphoma Group randomised trial

BACKGROUND

The long-term survival of patients with advanced stage aggressive lymphoma has not improved significantly during the last twenty years. In a randomised trial, the efficacy of MACOP-B, a six-drug weekly chemotherapy regimen, was compared to CHOP, the current standard regimen, in terms of overall and failure-free survival, toxicity and health related quality of life.

PATIENTS AND METHODS

Four hundred five patients with aggressive lymphoma, stage II-IV, age 18-67, were randomised to receive either 12 weeks of MACOP-B or 8 courses of CHOP over 24 weeks. Special emphasis was put in the definition of Ann Arbor stage in extranodal disease. A subset of 95 patients also entered a quality of life study, based on the EORTC QLQ-C30.

RESULTS

Thirty-one patients were ineligible. Among the remaining 374 patients, the median age was 52 years. According to the age-adjusted International Prognostic Index, 37% were 'high-intermediate' or 'high-risk' patients. No difference could be demonstrated, either in overall survival (60% at five years in the MACOP-B group and 59% in the CHOP group) or in failure-free survival (47% at five years with MACOP-B and 44% with CHOP). In terms of quality of life, physical function and global quality of life were more impaired in patients receiving MACOP-B, who also exhibited more non-haematological toxicity.

CONCLUSION

No superiority of MACOP-B compared to CHOP could be demonstrated. CHOP remains the treatment of choice in low-risk patients. At present, intensified or experimental treatment should be reserved for high-risk disease.

Combined modality treatment is the treatment of choice for stage I/IE intermediate and high grade non-Hodgkin's lymphomas

BACKGROUND AND PURPOSE

In a retrospective study, the efficacy of radiotherapy alone was compared with combined modality treatment in patients with stage I/IE non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Between 1980 and 1994, 296 patients with stage I/IE non-Hodgkin's lymphoma of intermediate or high grade malignancy (according to the Working Formulation) were treated in four different institutions. All patients were included except patients that presented with NHLs localized in the central nervous system, testis or skin. Two hundred two patients were treated with radiation therapy alone and 94 patients were treated with combined modality treatment.

RESULTS

Increasing age and radiation as a single treatment (versus combined modality treatment) were highly significant adverse prognostic factors by multivariate analysis. The actuarial 10-year rates for progression-free and overall survival were 83 and 70%, respectively, for the patients treated with combined modality treatment and 47 and 43%, respectively, for the patients treated with radiation therapy alone.

CONCLUSION

Combined modality treatment is the treatment of choice for patients with stage I/IE intermediate and high grade non-Hodgkin's lymphomas.