[Genetic analysis of 45 patients with suspected Lynch syndrome using next-generation sequencing]

Objective: To evaluate the value of next generation sequencing (NGS) in the genetic testing of Lynch syndrome. Methods: Immunohistochemical method was used to detect the expressions of DNA mismatch repair (MMR) proteins, including MutL homolog 1 (MLH1), PMS1 homolog 2 (PMS2), MutS homolog 2 (MSH2) and MutS homolog 6 (MSH6) in colorectal cancer, gastric cancer and endometrial cancer tissues collected from Shandong Provincial Hospital between 2016 and 2018. The genomic DNA of 45 patients who were suspected with Lynch syndrome was extracted from non-cancerous tissue paraffin samples, which were postoperatively confirmed by microscope. The mutations of 12 genes including MLH1 and MSH2 were detected using NGS. The germline mutant sites and significance were analyzed by bioinformatics technology and further confirmed by using Sanger sequencing. Results: The immunohistochemical results showed that the 45 cases of suspected Lynch syndrome included 22 cases of MLH1 and PMS2 deficient expression, 16 cases of MLH2 and MSH6 deficient expression, and 7 cases of MMR proteins normal expression. The NGS result showed that 28 cases of adjacent sample from colon cancer patients included 4 cases of MLH1 pathogenic mutation, 1 case of suspected MLH1 mutation, 2 cases of MLH2 pathogenic mutation, 2 cases of suspected MLH2 mutation. No MMR gene mutation was found in adjacent samples of 6 cases of rectal cancer, 6 cases of gastric cancer and 7 cases of colorectal cancer with MMR normal expression. One case of MLH1 or MHL2 pathogenic mutation and one case of MLH1 suspected mutation was detected in adjacent samples of 5 cases of endometrial cancer. Moreover, NGS also detected many other genes mutations and unreported gene mutation sites. Pathogenic and suspected MLH1 and MSH2 mutations were verified by Sanger sequencing. Conclusions: High-throughput NGS is a quick, accurate and reliable technique to identify gene variants in suspected Lynch syndrome patients. It has a wide application prospect for gene testing of tumors associated with Lynch syndrome.

Clinical efficacy of integral theory–guided laparoscopic integral pelvic floor/ligament repair in the treatment of internal rectal prolapse in females

BACKGROUND

Internal rectal prolapse (IRP) is one of the most common causes of obstructive constipation. The incidence of IRP in women is approximately three times that in men. IRP is mainly treated by surgery, which can be divided into two categories: Abdominal procedures and perineal procedures. This study offers a better procedure for the treatment of IRP.

AIM

To compare the clinical efficacy of laparoscopic integral pelvic floor/ligament repair (IPFLR) combined with a procedure for prolapse and hemorrhoids (PPH) and the laparoscopic IPFLR alone in the treatment of IRP in women.

METHODS

This study collected the clinical data of 130 female patients with IRP who underwent surgery from January 2012 to October 2014. The patients were divided into groups A and B. Group A had 63 patients who underwent laparoscopic IPFLR alone, and group B had 67 patients who underwent the laparoscopic IPFLR combined with PPH. The degree of internal rectal prolapse (DIRP), Wexner constipation scale (WCS) score, Wexner incontinence scale (WIS) score, and Gastrointestinal Quality of Life Index (GIQLI) score were compared between groups and within groups before surgery and 6 mo and 2 years after surgery.

RESULTS

All laparoscopic surgeries were successful. The general information, number of bowel movements before surgery, DIRP, GIQLI score, WIS score, and WCS score before surgery were not significantly different between the two groups (all P > 0.05). The WCS score, WIS score, GIQLI score, and DIRP in each group 6 mo, and 2 years after surgery were significantly better than before surgery (P < 0.001). In group A, the DIRP and WCS score gradually improved from 6 mo to 2 years after surgery (P < 0.001), and the GIQLI score progressively improved from 6 mo to 2 years after surgery (P < 0.05). In group B, the DIRP, WCS score and WIS score significantly improved from 6 mo to 2 years after surgery (P < 0.05), and the GIQLI score 2 years after surgery was significantly higher than that 6 mo after surgery (P < 0.05). The WCS score, WIS score, GIQLI score, and DIRP of group B were significantly better than those of group A 6 mo and 2 years after surgery (all P < 0.001, Bonferroni) except DIRP at 2 years after surgery. There was a significant difference in the recurrence rate of IRP between the two groups 6 mo after surgery (P = 0.011). There was no significant difference in postoperative grade I-III complications between the two groups (P = 0.822).

CONCLUSION

Integral theory–guided laparoscopic IPFLR combined with PPH has a higher cure rate and a better clinical efficacy than laparoscopic IPFLR alone.

Probing the Ferromagnetism and Spin Wave Gap in VI3 by Helicity-Resolved Raman Spectroscopy

Circularly polarized light carries light spin angular momentum, which may lead helicity-resolved Raman scattering to be sensitive to the electronic spin configuration in magnetic materials. Here, we demonstrate that all Raman modes in the 2D ferromagnet VI₃ show different scattering intensities to left and right circularly polarized light at low temperatures, which gives direct evidence of the time-reversal symmetry breaking. By measuring the circular polarization of the dominant Raman mode with respect to the temperature and magnetic field, the ferromagnetic (FM) phase transition and hysteresis behavior can be clearly resolved. Besides the lattice excitations, quasielastic scattering is detected in the paramagnetic phase, and it gradually evolves into the acoustic magnon mode at 18.5 cm^-1 in the FM state, which gives the spin wave gap that results from large magnetic anisotropy. Our findings demonstrate that helicity-resolved Raman spectroscopy is an effective tool to directly probe the ferromagnetism in 2D magnets.

Magnetic Order-Induced Polarization Anomaly of Raman Scattering in 2D Magnet CrI3

The recent discovery of 2D magnets has revealed various intriguing phenomena due to the coupling between spin and other degrees of freedoms (such as helical photoluminescence, nonreciprocal SHG). Previous research on the spin-phonon coupling effect mainly focuses on the renormalization of phonon frequency. Here we demonstrate that the Raman polarization selection rules of optical phonons can be greatly modified by the magnetic ordering in 2D magnet CrI₃. For monolayer samples, the dominant A_1g peak shows an abnormally high intensity in the cross-polarization channel at low temperatures, which is forbidden by the selection rule based on the lattice symmetry. For the bilayer, this peak is absent in the cross-polarization channel for the layered antiferromagnetic (AFM) state and reappears when it is tuned to the ferromagnetic (FM) state by an external magnetic field. Our findings shed light on exploring the emergent magneto-optical effects in 2D magnets.