Clinical characteristics and prognosis of primary and secondary diffuse large B-cell lymphoma of the pancreas / 中华血液学杂志

Objective: To analyze the clinical characteristics and prognosis of primary and secondary pancreatic diffuse large B-cell lymphoma (DLBCL) . Methods: Clinical data of patients with pancreatic DLBCL admitted at Shanghai Rui Jin Hospital affiliated with Shanghai Jiao Tong University School of Medicine from April 2003 to June 2020 were analyzed. Gene mutation profiles were evaluated by targeted sequencing (55 lymphoma-related genes). Univariate and multivariate Cox regression models were used to evaluate the prognostic factors of overall survival (OS) and progression-free survival (PFS) . Results: Overall, 80 patients were included; 12 patients had primary pancreatic DLBCL (PPDLBCL), and 68 patients had secondary pancreatic DLBCL (SPDLBCL). Compared with those with PPDLBCL, patients with SPDLBCL had a higher number of affected extranodal sites (P<0.001) and had higher IPI scores (P=0.013). There was no significant difference in the OS (P=0.120) and PFS (P=0.067) between the two groups. Multivariate analysis indicated that IPI intermediate-high/high risk (P=0.025) and double expressor (DE) (P=0.017) were independent adverse prognostic factors of OS in patients with pancreatic DLBCL. IPI intermediate-high/high risk (P=0.021) was an independent adverse prognostic factor of PFS in patients with pancreatic DLBCL. Targeted sequencing of 29 patients showed that the mutation frequency of PIM1, SGK1, BTG2, FAS, MYC, and MYD88 in patients with pancreatic DLBCL were all >20%. PIM1 (P=0.006 for OS, P=0.032 for PFS) and MYD88 (P=0.001 for OS, P=0.017 for PFS) mutations were associated with poor OS and PFS in patients with SPDLBCL. Conclusion: There was no significant difference in the OS and PFS between patients with PPDLBCL and those with SPDLBCL. IPI intermediate-high/high risk and DE were adverse prognostic factors of pancreatic DLBCL. PIM1, SGK1, BTG2, FAS, MYC, and MYD88 were common mutations in pancreatic DLBCL. PIM1 and MYD88 mutations indicated worse prognosis.

MreBCD-associated Cytoskeleton is Required for Proper Segregation of the Chromosomal Terminus during the Division Cycle of Escherichia Coli / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In prokaryotic organisms, the mechanism responsible for the accurate partition of newly replicated chromosomes into daughter cells is incompletely understood. Segregation of the replication terminus of the circular prokaryotic chromosome poses special problems that have not previously been addressed. The aim of this study was to investigate the roles of several protein components (MreB, MreC, and MreD) of the prokaryotic cytoskeleton for the faithful transmission of the chromosomal terminus into daughter cells.</p><p><b>METHODS</b>Strain LQ1 (mreB::cat), LQ2 (mreC::cat), and LQ3 (mreD::cat) were constructed using the Red recombination system. LQ11/pLAU53, LQ12/pLAU53, LQ13/pLAU53, LQ14/pLAU53, and LQ15/pLAU53 strains were generated by P1transduction of (tetO) 240 -Gm and (lacO) 240 -Km cassettes from strains IL2 and IL29. Fluorescence microscopy was performed to observe localization pattern of fluorescently-labeled origin and terminus foci in wild-type and mutant cells. SOS induction was monitored as gfp fluorescence from PsulA-gfp in log phase cells grown in Luria-Bertani medium at 37°C by measurement of emission at 525 nm with excitation at 470 nm in a microplate fluorescence reader.</p><p><b>RESULTS</b>Mutational deletion of the mreB, mreC, or mreD genes was associated with selective loss of the terminus region in approximately 40% of the cells within growing cultures. This was accompanied by significant induction of the SOS DNA damage response, suggesting that deletion of terminus sequences may have occurred by chromosomal cleavage, presumably caused by ingrowth of the division septum prior to segregation of the replicated terminal.</p><p><b>CONCLUSIONS</b>These results imply a role for the MreBCD cytoskeleton in the resolution of the final products of terminus replication and/or in the specific movement of newly replicated termini away from midcell prior to completion of septal ingrowth. This would identify a previously unrecognized stage in the overall process of chromosome segregation.</p>