Immunogenomic analyses associate immunological alterations with mismatch repair defects in prostate cancer.

BACKGROUND: Understanding the integrated immunogenomic landscape of advanced prostate cancer (APC) could impact stratified treatment selection. METHODS: Defective mismatch repair (dMMR) status was determined by either loss of mismatch repair protein expression on IHC or microsatellite instability (MSI) by PCR in 127 APC biopsies from 124 patients (Royal Marsden [RMH] cohort); MSI by targeted panel next-generation sequencing (MSINGS) was then evaluated in the same cohort and in 254 APC samples from the Stand Up To Cancer/Prostate Cancer Foundation (SU2C/PCF). Whole exome sequencing (WES) data from this latter cohort were analyzed for pathogenic MMR gene variants, mutational load, and mutational signatures. Transcriptomic data, available for 168 samples, was also performed. RESULTS: Overall, 8.1% of patients in the RMH cohort had some evidence of dMMR, which associated with decreased overall survival. Higher MSINGS scores associated with dMMR, and these APCs were enriched for higher T cell infiltration and PD-L1 protein expression. Exome MSINGS scores strongly correlated with targeted panel MSINGS scores (r = 0.73, P < 0.0001), and higher MSINGS scores associated with dMMR mutational signatures in APC exomes. dMMR mutational signatures also associated with MMR gene mutations and increased immune cell, immune checkpoint, and T cell-associated transcripts. APC with dMMR mutational signatures overexpressed a variety of immune transcripts, including CD200R1, BTLA, PD-L1, PD-L2, ADORA2A, PIK3CG, and TIGIT. CONCLUSION: These data could impact immune target selection, combination therapeutic strategy selection, and selection of predictive biomarkers for immunotherapy in APC. FUNDING: We acknowledge funding support from Movember, Prostate Cancer UK, The Prostate Cancer Foundation, SU2C, and Cancer Research UK.

Cyclin D1 overexpression in proliferation centres of small lymphocytic lymphoma/chronic lymphocytic leukaemia.

The recent publication reviewing the updated WHO classification commented on the presence of cyclin D1-positive cells in the proliferation centres (PC) of small lymphocytic lymphoma/chronic lymphocytic leukaemia (SLL/CLL). The figure quoted was 30%, which appeared higher than our experience. To assess cyclin D1 expression in PC of SLL/CLL cases, we performed a review of SLL/CLL cases diagnosed at the Royal Marsden Hospital between 1996 and 2009. Of 105 SLL/CLL cases, 16.2% showed expression of cyclin D1 in PC with none carrying the translocation t(11;14)(q13;q32). Our study and a review of the published literature suggest that this phenomenon occurs with a significantly lower prevalence than that described in the recent review of the updated WHO classification. We confirm that cyclin D1 expression is confined to PC with the typical small lymphocytes being negative. This finding is apparently unrelated to the translocation involving CCND1 and IGH genes.

Marginal zone lymphoma: Associated autoimmunity and auto-immune disorders.

Large epidemiological studies have shown a consistent increased risk for developing lymphoma in the setting of autoimmune disorders (AID). It is known that this link appears to be stronger for some AID and certain non-Hodgkin lymphoma subtypes e.g. Sjögren's syndrome and extra-nodal marginal zone lymphoma of the salivary gland, and thyroid MALT lymphoma in a background of Hashimoto's thyroiditis. B and T-cell hyperactivity due to chronic antigenic stimulation and the consequent presence of acquired lymphoid tissue seems to play a key role in the pathogenesis of AI-related lymphomas. Advanced age at diagnosis, prolonged disease course and disease severity are thought to increase the risk of lymphoma development in AID patients. There is increasing evidence that AI-related lymphomas constitute a different spectrum of entities indicating a different pathobiology with specific clinical features and treatment implications. This chapter will provide a general overview on the epidemiological aspects of the NHL-AID association focussing on marginal zone lymphomas - one of the NHL subtypes mostly implicated in the synchronous/metachronous association with AID. We will review the possible biological mechanisms involved and the risk factors in each autoimmune condition related to this lymphoma.