RESUMO
BACKGROUND AND AIM: Immune checkpoint inhibitors and their combination with other agents have recently been available in advanced hepatocellular carcinoma (HCC). Hence, a thorough understanding of the tumor microenvironment based on tumor samples is yet to be achieved. This study aimed to explore the tumor microenvironment in advanced HCC in terms of microsatellite instability-high (MSI-H) by using tumor samples from advanced HCC patients eligible for systemic therapy. METHODS: MSI-H was assessed by polymerase chain reaction, and the expression of mismatch repair proteins, PD-L1, CD8, VEGF, and HLA-class1 was evaluated by immunohistochemistry. Whole-exome sequencing was performed for MSI-H tumor samples. RESULTS: Of 50 patients, one (2.0%) was confirmed with MSI-H. In the MSI-H advanced HCC tumor, a high tumor mutation burden, infiltration of CD8+ lymphocytes, and low expression of VEGF were identified. Although PD-L1 expression was negative, there was shrinkage of tumor following pembrolizumab. However, another tumor nonresponsive to pembrolizumab was present simultaneously. Checking the Cancer Genome Atlas (TCGA) database, we found a similar case to this patient. The TCGA case had unique gene features of miR-21 and miR-155 overexpression and hypermethylation of the MSH2 gene. CONCLUSION: We identified a very small number of MSI-H cases in HCC using one tumor biopsy sample for each patient with advanced HCC. In addition, epigenetic aberrations possibly lead to MSI-H in HCC patients. Since different HCC clones might coexist in the liver, sampling from multiple tumors should be considered to clarify the true proportion of MSI-H in HCC and to analyze tumor microenvironments.
RESUMO
Bronchiolitis obliterans syndrome (BOS) occurring after hematopoietic stem cell transplantation (HSCT) for hematologic malignancies is a progressive and refractory disease, and lung transplantation (LTx) seems to be the only promising treatment. We report two cases of BOS after HSCT, which showed distinct clinical courses and were successfully treated with LTx. The respiratory symptoms and function of the two patients progressively deteriorated to a critical level during the waiting period. In one patient, recurrent and intractable pneumothoraxes consistent with thoracic air-leak syndrome (TALS) occurred, which were associated with pleuroparenchymal fibroelastosis. TALS could accelerate clinical deterioration, thus permitting a shorter waiting period for LTx.
