Recent studies have suggested that epigenetic inactivation of tumour-related genes by promoter methylation participates in the development of gastric cancer. We newly identified the frequently aberrant promoter methylation of alpha-1B-adrenergic receptor (ADRA1B) in colorectal cancer by methylation-sensitive representational difference analysis (MS-RDA) and examined the methylation status of the ADRA1B promoter in 34 paired samples of colorectal cancer and surrounding epithelial tissue, and 34 paired samples of gastric cancer and surrounding epithelial tissue. In colorectal cancers, only four of 34 (11.8%) tumours showed ADRA1B promoter methylation. In contrast, ADRA1B promoter methylation was detected in 24 of 34 (70.6%) gastric cancers and in 14 of 34 (41.2%) surrounding epithelial tissues. The frequency of ADRA1B promoter methylation was higher in gastric epithelial tissues with intestinal metaplasia (41.6%) than in those without intestinal metaplasia (25.0%). Reverse transcription -PCR detected reduced ADRA1B expression in 12 of 18 (66.7%) gastric cancers, and its promoter methylation was detected in 11 of these 12 (91.7%) gastric cancers with reduced ADRA1B expression. Thus, ADRA1B promoter is frequently methylated in gastric cancer. Our results suggest that the ADRA1B gene is an important tumour-related gene frequently involved in the development and progression of gastric cancer.
Objective:Rare disease Background:Calcified amorphous tumor (CAT) of the heart is a rare non-neoplastic intracardiac mass, which is composed of calcium deposition surrounded by amorphous fibrous tissue. The clinical presentation of cardiac CAT resembles that of other cardiac tumors or vegetation, though there is no previous report of a CAT complicated with infective endocarditis. Case Report:A 67-year-old male with a history of end stage renal failure and gastric cancer who was on adjuvant chemotherapy presented with a cardiac mass. The mass was resected and diagnosed as CAT pathologically. Two separate sets of blood cultures were positive for Enterococcus faecalis, thus, the patient was diagnosed with infective endocarditis. Antibiotic treatment was continued for 6 weeks after surgery, and the patient recovered uneventfully. However, he died from a complication of his gastric cancer 5 months later. Conclusions:This is the first report of CAT associated with infective endocarditis. Blood cultures should be obtained to differentiate infective endocarditis or CAT with infectious endocarditis from CAT alone, because CAT with infective endocarditis may present atypically and may be more likely to require antibiotic treatment along with surgery.
11576 Background: Malignant soft tissue tumor is a rare cancer with few therapeutic options. Recent genomic analysis of soft tissue sarcoma (STS) revealed a high degree of chromosomal instability (CIN) including genome-wide copy number alteration, aneuploidy, whole genome doubling and chromothripsis. In STS patients, we observed extensive somatic LOH, a hallmark of CIN, which is haploid of germline mutations/variants in cancer-related genes. CIN of STS genome implicates abnormalities in chromosome segregation and mitosis. So far, studies on this issue, however, have not been reported in STS patients. Methods: We recruited 155 patients with metastatic/recurrent malignant soft tissue tumors (135 female and 20 male, mean age 51 at analysis, 100 LMS, 19 LPS, 4 ESS, 3 UPS, 3 AS, 3 MPT, 3 GIST and others) with information of familial cancer burden. Whole exome sequencing and analysis were performed in both blood and tumor samples as described in 2018ASCO. KIF18A expression was assessed by immunohistochemistry. Results: Patients with tumors harboring less than 33% somatic LOH in a total of somatic and LOH mutations/variants in 595 COSMIC genes (n = 54) have a better prognosis than those (34-66%, n = 49, 67-100%, n = 52) with tumors harboring more LOH genes (5-year OS; 71% vs 52% or 46%, p = 0.0299, p = 0.0117, respectively). Neither TMB nor MSI status was associated with LOH. Of the genes involved in chromosome segregation and mitosis, we found that a family of ARHGAP genes which play a role in the spindle assembly and Aurora A kinase activation was frequently mutated in both tumor and germline genomes (n = 81 in a total of 155). Damaging ARHGAP mutations/variants in tumors are correlated with higher LOH values (54±3.4%, n = 81 vs. 39±3.3%, n = 74. mean±SE, p = 0.0021) and poor prognosis of patients (5-year OS; 58% n = 81 vs. 41% n = 74, p = 0.0098). We also found that elevated and robust expression of a mitotic kinesin KIF18A in tumors harboring higher LOH and/or damaging ARHGAP mutations/variants (n = 12) but not in lower LOH tumors without ARHGAP mutations/variants (n = 4). Conclusions: This study, for the first time, demonstrates that genetic abnormalities and aberrant expression of genes involved in chromosome segregation and mitosis in patients with malignant soft tissue tumors. The results reveal a novel target of drug discovery for incurable STS because CIN tumor cells are shown to be particularly vulnerable to KIF18A inhibition, while somatic, diploid cells are not.
11531 Background: Malignant soft tissue tumor is a rare cancer with few therapeutic options. Although recent genomic characterization of soft tissue sarcoma revealed massive CNA and an excess of polygenic burden of pathological germline variants, their clinical and therapeutic significance remains to be understood. Methods: We recruited 155 patients with malignant soft tissue tumors (135 female and 20 male, mean age 51, 100 LMS, 19 LPS, 4 ESS, 3 UPS, 3 AS, 3 MPT, 3 GIST and others) of confirmed metastasis/recurrence. Whole exome sequencing was performed as reported in 2018ASCO. The MSI status was analyzed by PCR. Tumor immune microenvironment was assessed by immunohistochemistry. Results: Of the 595 COSMIC genes, heterozygous germline mutations/variants of the genome-wide 0-44 genes (av. 9.7/tumor) showed somatic loss-of-heterozygosity (LOH) with allele frequency of more than 70%. Patients with less than 33% LOH (n=53) in the total of somatic and LOH mutations showed improved 5-year survival rate compared with those (n=102) with more LOH (71% vs 52%, p=0.037). LMS (n=100) had higher value of LOH mutations than other tumors (n=55)(av. 55.5 vs 31.2%, p<0.001). Two patients with bone metastasis, one from liver undifferentiated sarcoma (case 1) and the other from uterine LMS (case 2) were identified as MSI-High and resultant higher TMB of 6.48 and 6.60/Mb, respectively than 1.47/Mb in av. Tumors from both cases had de novo mutations of MMR deficiency as EXO I (A153V) and WRN (S1120F) in case 1 and MSH2 (G674D) in case 2. Case 1 with pleural dissemination was treated with 5 cycles of Pembrolizumab (200mg/body, d1 q3weeks) but was progressive disease, while case 2 had no evaluable lesion after surgical removal of bone metastasis. Number of CD8+ T-cell infiltration (TIL), one of the best parameter with response to PD-1 blockade, was much higher in case 2 than in case 1 (av. 907 vs 290/mm2). Case 2 had no LOH mutations while case 1 had 37% LOH with more total mutations in tumor (16.1 vs 85.9/Mb). Higher values of LOH (av. 67 vs 19%) were clearly correlated with decreased density of CD8+TIL in tumor tissues (av. 9.6 vs 429/mm2, n=5, p=0.018). Conclusions: Our results, for the first time, suggest that in malignant soft tissue tumors, accumulation of genome-wide LOH of germline mutations/variants, from which self-antigens could be generated, may influence tumor immune microenvironment, and thus influence immunotherapy response and survival of the patients.
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