Objective:To analyze the clinical features and mutation of myeloid differentiation factor 88 (MYD88) L265P in patients with diffuse large B-cell lymphoma (DLBCL) of central nervous system (CNS).Methods:The clinicopathological materials of 45 cases of DLBCL of CNS were retrospectively collected in Xuanwu Hospital, Capital Medical University from September 2014 to February 2017. The clinicopathological data were retrospectively analyzed, combined with immunohistochemistry, EB virus in situ hybridization, imaging and medical history. The mutation of MYD88 L265P gene was detected by pyrosequencing and its clinical significance was analyzed. Results:The age of the patients ranged from 42 to 82 years [(57.6±8.8) years], including 24 males and 21 females. Totally 93.3% (42/45) of the patients had supratentorial tumours, which were single or multiple. The cerebral hemisphere (31/45, 68.9%) was the most common involved site, and 21 cases (21/45, 46.7%) had multiple lesions. Histologically, DLBCL in the CNS showed diffuse infiltration of tumor tissue, some of which grew around blood vessels in a "sleeve" arrangement. CD 20 and CD 79a were diffusely and strongly positive. Thirty-nine cases (39/45, 86.7%) were non-germinal center B cell (non-GCB) subtype and 6 cases (6/45, 13.3%) were germinal center B cell (GCB) subtype. MYD88 L265P mutation was found in 64.4% (29/45) patients. There was statistically significant difference between non-GCB type (71.8%, 28/39) and GCB type DLBCL (1/6, P=0.017). Compared with the operation/biopsy group without chemotherapy, operation+chemotherapy, biopsy+chemotherapy, operation/biopsy+chemotherapy+stem cell transplantation can improve the survival and prognosis ( HR=0.05, 95% CI 0.01-0.33 , P=0.002; HR=0.04, 95% CI 0.01-0.36 , P=0.004; HR=0.01, 95% CI 0.00-0.17 , P=0.001; respectively). Conclusions:DLBCL of the CNS is aggressive tumor with poor prognosis, the clinical manifestations are complex and diverse, and the diagnosis is challenging. MYD88 L265P is a common and specific gene mutation in primary CNS lymphoma(PCNSL), which is of great significance in the diagnosis and treatment of lymphoma. The MYD88 L265P mutation was more frequently detected in non-GCB than GCB subtype. Chemotherapy can improve the survival rate of PCNSL patients. If chemotherapy achieves complete remission and autologous hematopoietic stem cell transplantation is performed, there may be a chance of long-term survival.

Mammalian mitochondrial genome encodes a small set of tRNAs, rRNAs, and mRNAs. The RNA synthesis process has been well characterized. How the RNAs are degraded, however, is poorly understood. It was long assumed that the degradation happens in the matrix where transcription and translation machineries reside. Here we show that contrary to the assumption, mammalian mitochondrial RNA degradation occurs in the mitochondrial intermembrane space (IMS) and the IMS-localized RNASET2 is the enzyme that degrades the RNAs. This provides a new paradigm for understanding mitochondrial RNA metabolism and transport.
Cell Line ; Humans ; Mitochondrial Membranes ; metabolism ; Protein Transport ; RNA ; biosynthesis ; chemistry ; metabolism ; RNA Stability ; RNA, Mitochondrial ; Ribonucleases ; metabolism ; Tumor Suppressor Proteins ; metabolism

Mitochondrial dysfunctions play major roles in ageing. How mitochondrial stresses invoke downstream responses and how specificity of the signaling is achieved, however, remains unclear. We have previously discovered that the RNA component of Telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53, and then exported back to the cytosol. Cytosolic TERC-53 levels respond to mitochondrial functions, but have no direct effect on these functions, suggesting that cytosolic TERC-53 functions downstream of mitochondria as a signal of mitochondrial functions. Here, we show that cytosolic TERC-53 plays a regulatory role on cellular senescence and is involved in cognition decline in 10 months old mice, independent of its telomerase function. Manipulation of cytosolic TERC-53 levels affects cellular senescence and cognition decline in 10 months old mouse hippocampi without affecting telomerase activity, and most importantly, affects cellular senescence in terc cells. These findings uncover a senescence-related regulatory pathway with a non-coding RNA as the signal in mammals.