SUMMARY Diffuse large B cell lymphoma (DLBCL) is the most common form of blood cancer and is characterized by a striking degree of genetic and clinical heterogeneity. This heterogeneity poses a major barrier to understanding the genetic basis of the disease and its response to therapy. Here, we performed an integrative analysis of whole exome sequencing and transcriptome sequencing in a cohort of 1001 DLBCL patients to comprehensively define the landscape of 150 genetic drivers of the disease. We characterized the functional impact of these genes using an unbiased CRISPR screen of DLBCL cell lines to define oncogenes that promote cell growth. A prognostic model comprising these genetic alterations outperformed current established methods: cell of origin, the International Prognostic Index comprising clinical variables, and dual MYC and BCL2 expression. These results comprehensively define the genetic drivers and their functional roles in DLBCL to identify new therapeutic opportunities in the disease.

Interim analysis after 2 to 3 cycles showed complete remission rate of 56%, partial remission rate of 22%, giving an overall response rate of 78%. On treatment completion, the overall-response rate became 81% (complete remission ‫؍‬ 66%, partial remission ‫؍‬ 15%). Response rates were similar for newly diagnosed or relapsed/refractory patients. At a median follow-up of 31 months (1-84 months), the 5-year overall survival was 50% and 4-year disease-free-survival was 64%. Multivariate analysis showed that international prognostic index was the most significant factor impacting on outcome and survivals. (Blood. 2012;120(15):2973-2980)

Key Points NK/T-cell lymphomas failing L-asparaginse, generally fatal, showed a high CR rate to PD1 blockade with pembrolizumab. Comprehensive clinical, radiologic, pathologic, and molecular assessments showed different patterns of CRs and PRs.

Natural killer (NK)/T-cell lymphomas and NK-cell leukemias are aggressive malignancies. Occurring worldwide, they show a predilection for Asian and South American populations. Neoplastic cells are surface CD3−, cytoplasmic CD3ε+, CD56+, cytotoxic-molecule positive, Epstein-Barr virus (EBV) positive, with germline T-cell receptor gene. Lymphomas occur commonly in the nasal and upper aerodigestive region. Occasional cases present in the skin, salivary gland, testis, and gastrointestinal tract. Rare cases are disseminated with lymphadenopathy, hepatosplenomegaly, and a leukemic phase. Positron emission tomography computed tomography is useful in staging, as lymphomas are 18-fluorodeoxyglucose avid. Quantification of circulating EBV DNA is an accurate biomarker of tumor load. Nasal NK/T-cell lymphomas present mostly with stage I/II disease. Concomitant/sequential chemotherapy and radiotherapy is standard treatment. Radiotherapy alone is inadequate because of high systemic failure rate. For stage III/IV nasal, nonnasal, and disseminated lymphomas, systemic chemotherapy is indicated. Regimens containing l-asparaginase and drugs unaffected by P-glycoprotein are most effective. Hematopoietic stem cell transplantation (HSCT) is not indicated for early-stage nasal lymphomas. HSCT for lymphomas not in remission has poor results. In advanced-stage nasal, nonnasal, disseminated, or relapsed lymphomas, HSCT may be considered when remission is achieved. Prognostic modeling and EBV DNA monitoring may be useful in risk stratification for HSCT.

Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignancy of putative NK-cell origin, with a minority deriving from the T-cell lineage. Pathologically, the malignancy occurs in two forms, extranodal NK/T-cell lymphoma, nasal type; and aggressive NK-cell leukaemia. Lymphoma occur most commonly (80%) in the nose and upper aerodigestive tract, less commonly (20%) in non-nasal areas (skin, gastrointestinal tract, testis, salivary gland), and rarely as disseminated disease with a leukemic phase. Genetic analysis showed mutations of genes involved in the JAK/STAT pathway, RNA assembly, epigenetic regulation, and tumor suppression. In initial clinical evaluation, positron emission tomography computed tomography, and quantification of plasma EBV DNA are mandatory as they are useful for response monitoring and prognostication. In stage I/II diseases, combined chemotherapy and radiotherapy (sequentially or concurrently) is the best approach. Conventional anthracycline-containing regimens are ineffective and should be replaced by non-anthracycline-containing regimens, preferably including L-asparaginase. Radiotherapy alone is associated with high systemic relapse rates and should be avoided. In stage III/IV diseases, non-anthracycline-regimens-containing L-asparaginase are the standard. In relapsed/refractory cases, blockade of the programmed death protein 1 has recently shown promising results with high response rates. In the era of effective non-anthracycline-containing regimens, autologous haematopoietic stem cell transplantation (HSCT) has not been shown to be beneficial. However, allogeneic HSCT may be considered for high-risk or advanced-stage patients in remission or relapsed/refractory patients responding to salvage therapy. Prognostic models taking into account presentation, interim, and end-of-treatment parameters are useful in triaging patients to different treatment strategies.

The programmed cell death protein 1 (PD1) is one of the checkpoints that regulates the immune response. Ligation of PD1 with its ligands PDL1 and PDL2 results in transduction of negative signals to T-cells. PD1 expression is an important mechanism contributing to the exhausted effector T-cell phenotype. The expression of PD1 on effector T-cells and PDL1 on neoplastic cells enables tumor cells to evade anti-tumor immunity. Blockade of PD1 is an important immunotherapeutic strategy for cancers. Pembrolizumab (Keytruda) is a humanized monoclonal anti-PD1 antibody that has been extensively investigated in numerous malignancies. In melanoma refractory to targeted therapy, pembrolizumab induced overall response rates (ORRs) of 21-34%. It was superior to another immune checkpoint inhibitor ipilimumab (Yervoy) in stage III/IV unresectable melanoma. In refractory non-small cell lung cancer (NSCLC), pembrolizumab induced ORRs of 19-25%. Based on these results, pembrolizumab was approved by the USA FDA for the treatment of advanced melanoma and NSCLC. Tumor cell PDL1 expression may be a valid response predictor. Molecular analysis also showed that tumors with high gene mutation burdens, which might result in the formation of more tumor-related neo-antigens, had better responses to pembrolizumab. In malignancies including lymphomas and other solid tumors, preliminary data showed that ORRs of around 20-50 % could be achieved. Adverse events occurred in up to 60% of patients, but grade 3/4 toxicities were observed in <10% of cases. Immune-related adverse events including thyroid dysfunction, hepatitis and pneumonitis are more serious and may lead to cessation of treatment.

Enteropathy-associated T-cell lymphoma (EATL) is a rare primary gastrointestinal T-cell lymphoma. A multicenter study from the Asia Lymphoma Study Group identified 38 EATL patients within a 19-year period. All cases were type II EATL. Men were affected twice as common as women, at a median age of 59 (23-89) years. None had a history of celiac disease. The sites of involvement were small bowel and stomach (5%), small bowel (63%), small and large bowel (16%), and large bowel (18%). Common presenting features were bowel perforation (34%), pain (32%), and obstruction (21%). Lymphomas showed monomorphic neoplastic lymphoid infiltrates that were CD3 1 (100%), CD56 1 (91%), TIA-1 1 (96%), CD4 -CD8 1 (63%), CD4 1 CD8 1 (19%), CD4 -CD8 -(16%), and CD4 1 CD8 -(3%). Epstein Barr virus was demonstrable in three cases. Despite chemotherapy and/or surgical resection, the overall response and complete response rates were poor at 46% and 38%. The median overall survival (OS) was 7 months and progression-free-survival (PFS) 1 month. Five patients underwent hematopoietic stem cell transplantation all were alive. Age and the prognostic index for peripheral T-cell lymphoma were not prognostically significant. Good performance status was associated with better OS (P 5 0.03), and response to initial treatment led to better OS and PFS (P < 0.001). Am. J. Hematol. 87:663-668, 2012. V

Few studies have examined Chinese patients with chronic hepatitis B who exhibit hepatitis B surface antigen (HBsAg) seroclearance. We comprehensively studied the biochemical, virological, histological, and clinical aspects of 92 patients with HBsAg seroclearance (median follow-up, 126 months). Ninety-two HBsAg-positive controls matched for age, sex, and duration of follow-up were also recruited. Liver biochemistry, serum hepatitis B virus (HBV) DNA levels, and development of clinical complications were monitored. Intrahepatic total and covalently closed circular (ccc) HBV DNA were measured quantitatively in 16 patients. HBV genotype was determined in 30 patients. The mean age at HBsAg seroclearance was 48.8 (؉ 13.81) years. There was a significant improvement in serum alanine aminotransferase levels after HBsAg seroclearance (p<0.0001). Patients with genotype B had a higher chance of HBsAg seroclearance than those with genotype C (P ‫؍‬ .014). Ninety-eight percent of patients had undetectable serum HBV DNA. Thirty-seven percent of patients had low titer of intrahepatic HBV DNA, mainly in the form of cccDNA (71%-100%). All 14 patients with liver biopsies had near normal histology. There was no difference in the risk of development of hepatocellular carcinoma (HCC) between patients with and without HBsAg seroclearance. However, the mean age of HBsAg seroclearance was significantly older in patients with HCC than in patients without HCC (P ‫؍‬ .016). In conclusion, patients with HBsAg seroclearance had favorable biochemical, virological, and histological parameters. Intrahepatic HBV DNA level was low and predominantly in the form of cccDNA. However, HCC could still develop, particularly in patients with cirrhosis who had HBsAg seroclearance at an older age. (HEPATOLOGY 2004;39:1694 -1701.) H epatitis B surface antigen (HBsAg) seroclearance is a rare event in Chinese patients with chronic hepatitis B virus (HBV) infection who acquire the disease early in life. The estimated annual incidence of HBsAg seroclearance is 0.1% to 0.8%. 1,2 Undetectable HBsAg in the serum is usually due to a decrease in viremia rather than the emergence of HBsAg mutants. 3 Some studies demonstrate a favorable outcome in terms of histological features and development of hepatocellular carcinoma (HCC). 2,4 However, these findings are not confirmed by other studies. 5,6 The presence of HBV DNA within the liver in patients with HBsAg seroclearance has been demonstrated in some studies, 7-9 but it is not known whether the intrahepatic HBV DNA is replicative or nonreplicative-that is, in the form of covalently closed circular (ccc) DNA. Also, it is uncertain how much residual virus is in extrahepatic reservoirs like peripheral blood mononuclear cells (PBMC).Therefore, we sought to determine the factors associated with and the significance of HBsAg seroclearance in Chinese HBV patients by examining the following parameters: (1) liver biochemistry, (2) HBV DNA in the serum and PBMC, (3) HBV genotypes, (4) intrahepatic total and cccDNA, (5) liver h...