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Diffuse large B‐cell lymphoma (DLBCL) is the most common subtype of lymphoma, accounting for 30% of non‐Hodgkin lymphomas. Although comprehensive analysis of genetic abnormalities has led to the classification of lymphomas, the exact mechanism of lymphomagenesis remains elusive. The Ets family transcription factor, PU.1, encoded by Spi1, is essential for the development of myeloid and lymphoid cells. Our previous research illustrated the tumor suppressor function of PU.1 in classical Hodgkin lymphoma and myeloma cells. In the current study, we found that patients with DLBCL exhibited notably reduced PU.1 expression in their lymphoma cells, particularly in the non‐germinal center B‐cell‐like (GCB) subtype. This observation suggests that downregulation of PU.1 may be implicated in DLBCL tumor growth. To further assess PU.1's role in mature B cells in vivo, we generated conditional Spi1 knockout mice using Cγ1‐Cre mice. Remarkably, 13 of the 23 knockout mice (56%) showed splenomegaly, lymphadenopathy, or masses, with some having histologically confirmed B‐cell lymphomas. In contrast, no wild‐type mice developed B‐cell lymphoma. In addition, RNA‐seq analysis of lymphoma cells from Cγ1‐Cre Spi1F/F mice showed high frequency of each monoclonal CDR3 sequence, indicating that these lymphoma cells were monoclonal tumor cells. When these B lymphoma cells were transplanted into immunodeficient recipient mice, all mice died within 3 weeks. Lentiviral‐transduced Spi1 rescued 60% of the recipient mice, suggesting that PU.1 has a tumor suppressor function in vivo. Collectively, PU.1 is a tumor suppressor in mature B cells, and decreased PU.1 results in mature B‐cell lymphoma development. [ABSTRACT FROM AUTHOR]

Ganglions are pseudocysts that develop from part of the joint capsule or tendon sheath and are filled with synovial fluid. In this report, we describe a case of external auditory canal obstruction caused by a temporomandibular joint (TMJ) ganglion that was thought to be related to osteoarthritis. A 62-year-old man with the chief complaint of swelling of the anterior wall of the left external auditory canal underwent cystectomy at the Department of Otorhinolaryngology. Histopathological examination revealed a ganglion. Three months later, the swelling reappeared; computed tomography revealed an enlarged left temporomandibular head, which prompted the patient to visit our department. Subsequently, the ear canal was completely obstructed due to worsened swelling, and TMJ arthroplasty and ear canalplasty were performed. Postoperatively, the patient recovered well with no recurrence of swelling. Ganglions that arise as masses in the external auditory canal may be accompanied by osteoarthritis. [ABSTRACT FROM AUTHOR]

Background: We investigated the impact of the COVID‐19 pandemic on oral cancer (OC), comparing diagnosis and number of pre‐operative days in the diagnosis of OC in 2019 (pre‐COVID‐19) and that in 2020 (during the COVID‐19 pandemic). Methods: Using data from a cancer registry‐based study on the impact of COVID‐19 on cancer care in Osaka (CanReCO), we collected details of sex, age, residential area, cancer site, date of diagnosis, clinical stage at first treatment and number of pre‐operative days in OC patients. Results: A total of 1470 OC cases were registered. Incidence of OC before and during COVID‐19 was 814 and 656 cases, respectively. During the first wave of the pandemic (March to May 2020), incidence was about half that in the same period in 2019 (2019; n = 271, 2020; n = 145). Number of pre‐operative days (median number of days between the first hospital visit and surgery date) was significantly shorter during the COVID‐19 year (24.5 days) than in the pre‐COVID‐19 year (28 days, p = 0.0015). Conclusions: Incidence of OC during the COVID‐19 pandemic was lower than in pre‐COVID‐19. Despite disruption in the healthcare system, the number of pre‐operative days for OC cases was shorter during the pandemic. [ABSTRACT FROM AUTHOR]

Background: Liver biopsy is the gold standard for diagnosing TCMR after LT. However, complications caused by liver biopsy may occur especially during the immediate post‐transplantation period and other effective methods for predicting TCMR have not been established. Thus, we investigated whether hematological and biochemical characteristics and Doppler ultrasonography findings are associated with acute TCMR. Methods: A multiple logistic regression analysis was performed to identify the prognostic factors of acute TCMR, defined as a RAI ≥4. Then, a ROC curve analysis was conducted to evaluate for diagnostic performance. The relationship between prognostic factors and each histological category of RAI was investigated. Results: Eighty‐nine liver biopsies were performed on 85 patients between January 2012 and December 2019. The RAI of 62 (69.7%) liver biopsies was ≥4. AEC (×104/μl), direct bilirubin level (mg/dl), and MHVV (cm/s) were found to be associated with acute TCMR (OR: 4.96, 95% CI: 1.44–17.0, p =.011; OR: 1.41, 95% CI: 1.04–1.91, p =.025; OR: 1.05, 95% CI: 1.02–1.08, p <.001, respectively). The area under the ROC curves for predicting acute TCMR was 0.86 (95% CI: 0.78–0.94). There was a correlation between AEC, direct bilirubin level, and MHVV as well as the severity of RAI. Conclusions: AEC, direct bilirubin level, and MHVV were the independent risk factors for acute TCMR. This study could provide information regarding the identification of patients requiring liver biopsy. [ABSTRACT FROM AUTHOR]