ancer immunotherapies have shown promise in harnessing the immune system to target and destroy cancers, leading to clinical benefit enriched in patients with a high mutational burden [1][2][3][4][5] . Multiple studies indicate that cytotoxic CD8 T cells targeting tumor neoantigens are critical to tumor control and clearance in response to immunotherapies targeting CTLA-4 or PD-1 [6][7][8][9][10] . Clinical responses to CPI therapy rely mostly on reinvigorating preexisting tumor-specific T cell responses 11 , and active vaccination to expand preexisting and prime de novo tumor-specific T cells is anticipated to overcome this limitation.The limited success of cancer vaccines in the past can be attributed to a number of factors, including selection of poorly immunogenic self-antigens 12 , insufficiently immunogenic vaccine platforms and immunosuppressive milieus in patients with advanced cancers 4 . Accordingly, peptide-based neoantigen vaccine platforms have to date failed to consistently induce robust neoantigen-specific CD8 T cell responses in the majority of patients [13][14][15] . Although more immunogenic, a homologous prime boost messenger RNA (mRNA)-based vaccination approach elicited predominantly CD4 T cell responses [16][17][18] . Cumulatively, previous findings suggest that a successful cancer vaccine should (1) target tumor-specific neoantigens, (2) use highly immunogenic vaccine platform(s), (3) expand and prime T cells, (4) be combined with CPI therapy 19 and (5) generate long-term memory responses to ensure continuous tumor control for durable clinical benefit.Viral vector-based vaccine platforms, such as recombinant adenovirus, are able to prime robust T cell responses [20][21][22][23][24] . Although high seroprevalence of anti-adenoviral antibodies in human populations

Listeria monocytogenes lineages III and IV represent two uncommon lineages of the human and animal pathogen L. monocytogenes, characterized by occurrence of unusual phenotypic and genetic characteristics that differentiate them from the common lineages I and II. To gain further insights into the evolution of lineages III and IV, we amplified and sequenced housekeeping genes (i.e., gap, prs, purM, ribC, and sigB), internalin genes (i.e., inlA, inlB, inlC, inlG, inlC2, inlD, inlE, inlF, and inlH) and the virulence gene cluster containing prfA, plcA, hly, mpl, actA, and plcB for lineage III (n=7) and IV (n=4) isolates. Phylogenetic analyses of the sequences obtained along with previously reported sequence data for 40 isolates representing lineages I (n=18), II (n=21), and III (n=1), showed that lineages III and IV represent divergent and monophyletic lineages. The virulence gene cluster as well as the inlAB operon were present in all isolates, with inlF absent from all lineage III and IV isolates. While all lineage IV isolates contained only inlC (in addition to inlAB), lineage III isolates showed considerable diversity with regard to internalin gene presence, including presence of (i) only inlC (n=2), (ii) inlC and inlGC2DE (n=3), (iii) only inlGC2DE (n=2), and (iv) inlC and inlC2DE (n=1). In addition to evidence for horizontal gene transfer events, among lineage III and IV isolates, in prs, actA, plcB, mpl, inlA, inlB, inlG, inlD, and inlE, we also found significant evidence for positive selection in the hly promoter region and, along the lineage III and IV branches, for actA (including in sites recognized for interactions with proteins involved in actin tail polymerization). In conclusion, lineages III and IV represent two distinct monophyletic groups with contributions of intragenic recombination to the evolution of their internalin genes as well as contributions of positive selection to evolution of the virulence genes island.

Missense mutations in the polymerase epsilon (POLE) gene have been reported to generate proofreading defects resulting in an ultramutated genome and sensitize tumors to checkpoint blockade immunotherapy. However, many POLE mutated tumors do not respond to such treatment. To better understand the link between POLE mutation variants and response to immunotherapy, we. prospectively assessed the efficacy of nivolumab in a multicenter clinical trial in patients bearing advanced mismatch repair proficient POLE-mutated solid tumors. We found that only tumors harboring selective POLE pathogenic mutations in the DNA binding or catalytic site of the exonuclease domain presented high mutational burden with specific single base substitution signature, high T-cell infiltrates, and high response rate to anti-PD1 monotherapy. This study illustrates how specific DNA repair defects can sensitize to immunotherapy, POLE proofreading deficiency representing a novel tumor agnostic biomarker for response to PD-1 checkpoint blockade therapy.

IMPORTANCE Among patients with esophagogastric cancers, only individuals who present with known features of heritable cancer syndromes are referred for genetic testing. Broader testing might identify additional patients with germline alterations.OBJECTIVES To examine the prevalence of likely pathogenic or pathogenic (LP/P) germline alterations among patients with esophagogastric cancer and to assess associations between germline variant prevalence and demographic and clinicopathologic features. DESIGN, SETTING, AND PARTICIPANTSThis cross-sectional study was performed at a tertiary referral cancer center from January 1, 2014, to December 31, 2019, in 515 patients with esophagogastric cancer who consented to tumor and blood sequencing. MAIN OUTCOMES AND MEASURES Presence or absence of LP/P variants in up to 88 genes associated with cancer predisposition syndromes as identified by targeted sequencing (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets). RESULTS Among 515 patients (median age, 59 years; range, 18-87 years; 368 [71.5%] male; 398 [77.3%] White), 243 (47.2%) had gastric cancer, 111 (21.6%) had gastroesophageal junction (GEJ) cancer, and 161 (31.3%) had esophageal cancer. A total of 48 patients with gastric cancer (19.8%), 16 (14.4%) with GEJ cancer, and 17 (10.6%) with esophageal cancer had LP/P germline variants. The number of LP/P variants in high-and moderate-penetrance genes was significantly higher in patients with gastric cancer (29 [11.9%]; 95% CI, 8.1%-16.7%) vs patients with esophageal cancer (8 [5.0%];95% CI, 2.2%-9.6%; P = .03), and the difference was greater for high-penetrance germline alterations in patients with gastric cancer (25 [10.3%]; 95% CI, 6.8%-14.8%) vs in patients with esophageal cancer (3 [1.9%]; 95% CI, 0.38%-5.3%; P = .001). The most frequent high-and moderate-penetrance LP/P alterations were in BRCA1/2 (14 [2.7%]), ATM (11 [2.1%]), CDH1 (6 [1.2%]), and MSH2 (4 [0.8%]). Those with early-onset disease (Յ50 years of age at diagnosis) were more likely to harbor an LP/P germline variant (29 [21.0%]; 95% CI, 14.5%-28.8%) vs those with late-onset disease (patients >50 years of age at diagnosis) (52 [13.8%]; 95% CI, 10.5%-17.7%; P = .046). ATM LP/P variants occurred in 6 patients (4.3%; 95% CI, 1.6%-9.1%) with early-onset esophagogastric cancer vs 5 (1.3%; 95% CI, 0.4%-3.1%; P = .08) of those with late-onset esophagogastric cancer. CONCLUSIONS AND RELEVANCEThese results suggest that pathogenic germline variants are enriched in gastric and early-onset esophagogastric cancer and that germline testing should be considered in these populations. The role of ATM alterations in esophagogastric cancer risk warrants further investigation.