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Objective:To explore KRAS, NRAS, BRAF gene mutations and microsatellite instability(MSI) in colorectal cancer tissues as well as their correlation with the clinicopathological characteristics of patients.Methods:The clinicopathological data of 473 colorectal cancer patients in Shanxi Province Cancer Hospital from October 2020 to May 2021 were retrospectively analyzed. The mutation status of KRAS, NRAS and BRAF gene in the paraffin tissues were detected by using amplification refractory mutation system (ARMS) method. Polymerase chain reaction (PCR)-capillary electrophoresis was used to analyze MSI status, and the correlation of the clinicopathological characteristics of patients with gene mutations and MSI status was analyzed.Results:The mutation rates of KRAS, NRAS and BRAF were 45.03% (213/473), 2.96% (14/473) and 5.50% (26/473), respectively in 473 patients with colorectal cancer. No case harbored both 2 gene mutations was detected. The mutation rate of KRAS gene in well differentiated adenocarcinoma was higher than that in poorly differentiated adenocarcinoma [47.4% (175/369) vs. 36.5% (38/104), χ2 = 3.89, P = 0.049]. NRAS mutation rate in female was higher than that in male [5.0% (10/202) vs. 1.5% (4/271), χ2 = 4.86, P = 0.027], and the NRAS mutation rate in patients with tumor diameter ≤ 3 cm was higher than that in those with tumor diameter >3 cm [7.1% (7/98) vs. 1.9% (7/375), P = 0.013]. BRAF mutation rate of tumors located in colon was higher than that in rectum [11.7% (20/171) vs.2.0% (6/302), χ2 = 19.81, P < 0.001]; BRAF mutation rate in poorly differentiated tumor was higher than that in well differentiated tumor [10.6% (11/104) vs. 4.1% (15/369), χ2 = 6.62, P = 0.010]; BRAF mutation rate in patients with mucus was higher than that in those without mucus [10.9% (11/101) vs. 4.0% (15/372), χ2 = 7.19, P = 0.007]; BRAF mutation rate in patients with lymphatic metastasis was higher than that in patients without lymphatic metastasis [8.2% (15/182) vs.3.8% (11/291), χ2 = 4.29, P = 0.038]. The incidence of high frequency MSI (MSI-H) in 473 colorectal cancer tissues was 7.19% (34/473). The incidence of MSI-H in colon was higher than that in rectum [14.0% (24/171) vs. 3.3% (10/302), χ2 = 18.82, P < 0.001]; the incidence of MSI-H in patient with poor differentiated tumor was higher than that in those with well differentiated tumor [17.3% (18/104) vs. 4.3% (16/369), χ2 = 20.46, P < 0.001]; the incidence of MSI-H in patients with mucus was higher than that in those without mucus [11.9% (12/101) vs. 5.9% (22/372), χ2 = 4.24, P = 0.039]; and the incidence of MSI-H in patients without lymphatic metastasis was higher than that in patients with lymphatic metastasis [10.0% (29/291) vs. 2.7% (5/182), χ2 = 8.75, P = 0.003]. In addition, the incidence of MSI-H was on the rise in patients with BRAF mutation ( P < 0.001). Conclusions:KRAS, NRAS, BRAF gene mutations and MSI status are correlated with the clinicopathological characteristics of patients with colorectal cancer; there is a close relationship between MSI-H and BRAF mutation.
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Objective:To analyze the value of droplet digital polymerase chain reaction (ddPCR) in detecting epidermal growth factor receptor (EGFR) mutations in peripheral blood circulating tumor DNA (ctDNA) of patients with non-small cell lung cancer (NSCLC).Methods:Peripheral blood samples of 63 patients with NSCLC who were treated in Shanxi Provincial Cancer Hospital from August 2018 to March 2019 were collected, and EGFR sensitive mutations in peripheral blood of patients were detected by ddPCR, and the results were compared with the results of amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Kappa test was used to analyze the consistency of the two methods.Results:The EGFR sensitive mutations were found in 31 cases (49.2%) by ddPCR in peripheral blood of 63 patients with NSCLC. Among them, 1 case (1.6%) had G719X, 12 cases (19.0%) had E19-Del, 11 cases had T790M (17.5%), 7 cases (11.1%) had L858R. Seven cases (22.6%) of the patients had double mutations. In comparison, the above 4 mutations were found in 26 cases (41.3%) by the ARMS-PCR method, with 0 case, 12 cases (19.0%), 6 cases (9.5%), and 8 cases (12.7%), respectively, including 5 cases (19.2%) with double mutations. L858R in one case was positive when detected by ARMS-PCR, while it was negative when detected by ddPCR. The consistency rate of the two methods was 90.3% (κ = 0.8, P < 0.05). The median abundance of EGFR mutations in peripheral blood ctDNA of 31 cases was 1.7% (range 0.04%-23.60%). The median abundance of E19-Del was 2.50% (0.35%-22.70%), that of T790M was 0.6% (0.04%-14.00%), and that of L858R was 2.3% (0.20%-23.60%). Ten cases with the abundance of EGFR mutations < 1% when detected by ddPCR, accounting for 32.6% (10/31) of total patients with mutations, but only 5 cases of them were detected by ARMS-PCR. The detection rate of T790M by ddPCR in patients who had received tyrosine kinase inhibitor (TKI) and had acquired drug resistance was 57.9% (11/19), while it was 0 in patients without TKI treatment. Among patients with T790M mutation, 1 case had a mutation abundance < 0.1%, 7 cases had a mutation abundance of 0.1%-2.0%, 3 cases had a mutation abundance > 2.0%.Conclusions:The ddPCR provides a non-invasive, highly sensitive and absolutely quantitative method for detecting EGFR mutations in peripheral blood ctDNA of NSCLC patients. It provides a new detection method for EGFR-TKI targeted therapy in NSCLC patients with difficult sampling or with acquired drug resistance who need to repeatedly sample. The approach provides an important basis for the individualized targeted therapy.
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Objective To find noninvasive estimation of partial pressure of carbon dioxide in artery (PaCO2) by measuring the end-tidal CO2 partial pressure (PETCO2) in elderly patients with respiratory failure with chronic obstructive pulmonary disease (COPD). Methods All the 30 acutely exacerbated COPD subjects received routine clinical treatment including bronchodilators,mucolytics, glucocorticosteroid, antibiotics and oxygen therapy for 5-7 days, and part of them received noninvasive positive-pressure ventilation (NIPPV) treatment concurrently. They were both tested by eupnea method and prolonged expiratory method before and after treatment. Results Before treatment, PET CO2 (Q) (end-tidal CO2 pressure with eupnea, (50.72±8.93) mm Hg wassignificantly lower than PaCO2 (F=38.73, P＜0.01 ). Yet, PETCO2(P) (end-tidal CO2 pressure with prolong expiration) was (70.35±8.91) mm Hg and PaCO2 was (71.25±9.08) mm Hg. There was no significant difference between PETCO2 (P) and PaCO2 (P＞0.05). The similar results were found after treatment. By linear regression analysis, PetCO2(P) was remarkably positive correlated with PaCO2 before and after treatment (r=0.96 and 0.97, respectively, P＜0.01). According to TABG,PCO2(C) which was calculated by the average expiratory time of fitting curve was (71.78±9.04)mm Hg. And there was no significant difference between PCO2 (C) and PaCO2 (P＞0.05);Thesimilar results were founcl after treatment. By linear regression analysis, PCO2 (C) was remarkably positively correlated with PaCO2 (r=0.97 and 0.98, respectively, P＜0.01) before and after treatment. Conclusions In COPD patients with type Ⅱ respiratory failure, conventional PETCO2 (Q) is significantly lower than PaCO2. Yet, PETCO2 (P) could exactly estimate PaCO2 and is appropriate to its dynamic monitoring. And PCO2 (C) which is calculated by mode Boltzmann on eupnea curve also obtain similar results.