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IntroductionMyeloid sarcomas (MS) comprise rare extramedullary manifestations of myeloid neoplasms with poor patients’ outcome. While the clinical relevance of the tumor microenvironment (TME) is well established in many malignancies, there exists limited information in MS. MethodsThe expression of the human leukocyte antigen class I (HLA-I) antigens, HLA-I antigen processing and presenting machinery (APM) components and the composition of the TME of 45 MS and paired bone marrow (BM) samples from two independent cohorts were assessed by immunohistochemistry, multispectral imaging, and RNA sequencing (RNAseq).ResultsA significant downregulation of the HLA-I heavy chain (HC; 67.5%) and ß2-microglobulin (ß2M; 64.8%), but an upregulation of HLA-G was found in MS compared to BM samples, which was confirmed in a publicly available dataset. Moreover, MS tumors showed a predominantly immune cell excluded TME with decreased numbers of tissue infiltrating lymphocytes (TILs) (9.5%) compared to paired BM (22.9%). RNAseq analysis of a subset of 10 MS patients with preserved and reduced HLA-I HC expression revealed 150 differentially expressed genes and a significantly reduced expression of inflammatory response genes was found in samples with preserved HLA-I expression. Furthermore, low HLA-I expression and low TIL numbers in the TME of MS cases were linked to an inferior patients’ outcome.DiscussionThis study demonstrated a high prevalence of immune escape strategies in the pathogenesis and extramedullary spread of MS, which was also found in patients without evidence of any BM pathology, which yields the rational for the development of novel individually tailored therapies for MS patients.

Summary: Background: DNA methylation biomarkers in colorectal cancer (CRC) tissue hold potential as prognostic indicators. However, individual studies have yielded heterogeneous results, and external validation is largely absent. We conducted a comprehensive external validation and meta-analysis of previously suggested gene methylation biomarkers for CRC prognosis. Methods: We performed a systematic search to identify relevant studies investigating gene methylation biomarkers for CRC prognosis until March 2024. Our external validation cohort with long-term follow-up included 2303 patients with CRC from 22 hospitals in southwest Germany. We used Cox regression analyses to assess associations between previously suggested gene methylation biomarkers and prognosis, adjusting for clinical variables. We calculated pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) using random-effects models. Findings: Of 151 single gene and 29 multiple gene methylation biomarkers identified from 121 studies, 37 single gene and seven multiple gene biomarkers were significantly associated with CRC prognosis after adjustment for clinical variables. Moreover, the directions of these associations with prognosis remained consistent between the original studies and our validation analyses. Seven single biomarkers and two multi-biomarker signatures were significantly associated with CRC prognosis in the meta-analysis, with a relatively strong level of evidence for CDKN2A, WNT5A, MLH1, and EVL. Interpretation: In a comprehensive evaluation of the so far identified gene methylation biomarkers for CRC prognosis, we identified candidates with potential clinical relevance for further investigation. Funding: The German Research Council, the Interdisciplinary Research Program of the National Center for Tumor Diseases (NCT), Germany, the German Federal Ministry of Education and Research.

BackgroundRecently, we could show that the co-mutations of KRAS + KEAP1, STK11 + KEAP1 and KRAS + STK11 + KEAP1 lead to a significantly shorter median overall survival (mOS) in patients with lung cancer across treatments by analyzing multiple dataset. TP53, a tumor suppressor gene, plays a crucial role in regulating cell cycle progression. Its mutations occur in approximately 40-50% of non-small lung cancer (NSCLC). Co-occurrence of all four mentioned mutations has been a matter of debate for years. The aim of this study was to assess the distribution of these four mutations and the influence of the different co-mutational patterns on survival.MethodsWe present a comparative bioinformatic analysis and refer to data of 4,109 patients with lung adenocarcinoma (LUAD).ResultsMost of the mutations within the LUAD belong to TP53-only (29.0%), quadruple-negative (25.9%) and KRAS-only (13.4%). Whereas TP53-mutations seem to have protective effects in the context of further KEAP1- and KRAS + KEAP1-alterations (improved mOS), their role seems contrary if acquired in an already existing combination of mutations as KRAS + STK11, KRAS + STK11 + KEAP1 and STK11 + KEAP1. TP53 co-mutations had a negative influence on KRAS-only mutated LUAD (mOS reduced significantly by more than 30%).DiscussionThese data underline the need for complex mutational testing to estimate prognosis more accurately in patients with advanced LUAD.