[Clinicopathological features of patients with RET fusion-positive non-small cell lung cancer]

Objective: To investigate the clinicopathological features, treatment and prognosis of patients with RET fusion positive non-small cell lung cancer (NSCLC). Methods: A total of 1 089 NSCLCs were retrieved at Affiliated Hospital of Jiangnan University from August 2018 to April 2020. In all cases, multiple gene fusion detection kits (fluorescent PCR method) were used to detect the gene status of RET, EGFR, ALK, ROS1, KRAS, BRAF and HER2; and immunohistochemical method was used to detect the expression of PD-L1 and mismatch repair related proteins. The correlation between RET-fusion and patients' age, gender, smoking history, tumor stage, grade, pathologic type, and PD-L1, mismatch repair related protein expression was analyzed. Results: There were 22 cases (2.02%) detected with RET fusion-positive in 1 089 NSCLC patients, in which 11 males and 11 females; and the median age was 63.5 years. There were 20 adenocarcinomas, including 11 acinar predominant adenocarcinoma (APA), five solid predominant adenocarcinoma (SPA) and four lepidic predominant adenocarcinoma (LPA); There were one case each of squamous cell carcinoma (non-keratinizing type) and sarcomatoid carcinoma (pleomorphic carcinoma). There were 6 and 16 patients with RET fusion-positive who were in stage Ⅰ-Ⅱ and Ⅲ-Ⅳ respectively, and 16 cases with lymph node metastasis, 11 cases with distant metastasis. Among RET fusion-positive cases, one was detected with HER2 co-mutation. The tumor proportion score of PD-L1≥1% in patients with RET fusion positive lung cancer was 54.5% (12/22). Defects in mismatch repair protein expression were not found in patients with RET fusion positive NSCLC. Four patients with RET fusions positive (two cases of APA and two cases of SPA) received pratinib-targeted therapy, and two showed benefits from this targeted therapy. Conclusions: The histological subtypes of RET fusions positive NSCLC are more likely to be APA or SPA. RET fusion-positive NSCLC patients are associated with advanced clinical stage, lymph node metastases, and they may benefit from targeted therapy with RET-specific inhibitors.

[Study on efficacy, recurrence rate and related risk factors between ablation index and contact force guided radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients]

Objective: To compare the efficacy, safety and recurrence rate between ablation index (AI) and contact force (CF) guided radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients. Methods: Elderly patients (age ≥60 years) with paroxysmal atrial fibrillation who received radiofrequency ablation for the first time at Department of Cardiology, Beijing Friendship Hospital from April 2018 to April 2019 were enrolled. Patients were divided into 2 groups: AI-group (n=40) and CF group (n=37) depending on their ablation methods. Follow-up was performed until 1 year post the procedure, and efficacy related indexes like first-pass pulmonary vein isolation (PVI) rate, ablation duration, operation duration and major complications were compared between 2 groups. The recurrence rates between 2 groups and related risk factors after radiofrequency ablation were analyzed. Results: A total of 77 patients [mean age (68.5±6.4) years, 40 were male] were enrolled at last. In AI guided patients, frequency of first-pass PVI rate was higher [52.5%(21 cases) vs 29.7%(3 cases), P=0.011] with a shorter ablation duration [(24.5±1.7) min vs (33.7±2.2) min, P<0.001] and operation duration [(136.6±6.1) min vs (139.7±7.4) min, P=0.048] compared with CF guided group. At 1 year follow-up, AI group showed an amendatory recurrence rate in Kaplan-Meier analysis (22.5% vs 40.5%,log-rank P=0.048). Multivariate Cox regression analysis showed that CF guided ablation (HR=3.272,95%CI:1.319-8.114,P=0.011), enlarged anteroposterior diameter of the left atrium (HR=4.233,95%CI:1.511-11.862,P=0.006) and complicated with coronary heart disease (HR=4.829,95%CI:1.399-16.666,P=0.013) were independent risk factors for recurrence of atrial fibrillation in elderly patients. Conclusions: Compared with CF guided ablation, radiofrequency ablation of paroxysmal atrial fibrillation in elderly patients guided by AI showed a higher first-pass PVI rate, shorter procedure duration of both ablation time and total operation time, meanwhile a lower recurrence rate. Further analysis revealed that different ablation alternation (AI or CF), enlarged anteroposterior diameter of left atrium, and complicated with coronary heart disease are independent risk factors for recurrence after radiofrequency ablation of atrial fibrillation in elderly patients.

Studies on expression of p14ARF and MDM2 in human thyroid neoplasms

AIM

We sought to evaluate the expression and clinical significance of p14ARF and MDM2 proteins in thyroid neoplasm.

METHODS

Immunohistochemical streptavidin-peroxidase (S-P) method was used to detect the expression of p14ARF and MDM2 proteins in 78 cases of papillary thyroid carcinoma (PTC), 34 cases of papillary thyroid microcarcinoma (PTMC) and 45 cases of thyroid adenoma.

RESULTS

The expression of p14ARF and MDM2 protein differed significantly (P<0.01) among three group. The positivity rate of p14ARF protein in PTC was significantly lower than that in thyroid adenoma (P=0.002) and PTMC (P=0.008). While the positivity rate of MDM2 protein in PTC was significantly higher than that in thyroid adenoma (P=0.000) and PTMC (P=0.009). There was a significant correlation found between the expressions of p14ARF and MDM2 proteins in PTC (P=0.013) and PTMC (P=0.012). Also, a significant correlation was found between p14ARF protein expression and lymph node metastasis in PTC (P=0.011).

CONCLUSION

It was concluded that p14ARF and MDM2 proteins might be involved in the induction and development of PTC and PTMC whereas p14ARF also had diagnostic value in determining the biological behavior of PTC.

Repair of articular cartilage defects by tissue-engineered cartilage constructed with adipose-derived stem cells and acellular cartilaginous matrix in rabbits

After injury, inflammation, or degeneration, articular cartilage has limited self-repair ability. We aimed to explore the feasibility of repair of articular cartilage defects with tissue-engineered cartilage constructed by acellular cartilage matrices (ACMs) seeded with adipose-derived stem cells (ADSCs). The ADSCs were isolated from 3-month-old New Zealand albino rabbit by using collagenase and cultured and amplified in vitro. Fresh cartilage isolated from adult New Zealand albino rabbit were freeze-dried for 12 h and treated with Triton X-100, DNase, and RNase to obtain ACMs. ADSCs were seeded in the acellular cartilaginous matrix at 2x10(7)/mL, and cultured in chondrogenic differentiation medium for 2 weeks to construct tissue-engineered cartilage. Twenty-four New Zealand white rabbits were randomly divided into A, B, and C groups. Engineered cartilage was transplanted into cartilage defect position of rabbits in group A, group B obtained ACMs, and group C did not receive any transplants. The rabbits were sacrificed in week 12. The restored tissue was evaluated using macroscopy, histology, immunohistochemistry, and transmission electron microscopy (TEM). In the tissue-engineered cartilage group (group A), articular cartilage defects of the rabbits were filled with chondrocyte-like tissue with smooth surface. Immunohistochemistry showed type II-collagen expression and Alcian blue staining was positive. TEM showed chondrocytes in the recesses, with plenty of secretary matrix particles. In the scaffold group (group B), the defect was filled with fibrous tissue. No repaired tissue was found in the blank group (group C). Tissue-engineered cartilage using ACM seeded with ADSCs can help repair articular cartilage defects in rabbits.

A unique surface-initiated property of nanoparticles and application for the synthesis of hybrid organic–inorganic nanoparticles

Fe₃O₄ nanoparticles initiate the polymerization of a vinyl monomer of acrylamide on the surface to form novel organic–inorganic hybrid nanomaterials.