Circulating tumor cells ( CTCs ) exists in peripheral blood of patients with a variety of malignant tumors , the accurate detection of CTCs helps early detection of cancer , and can be used to guide individualized treatment of cancer patients , rapid assessment of tumor chemotherapy drugs and detection of tumor recurrence .However , the CTCs in peripheral blood of cancer patients were extremely low , their detection requires efficient and specific enrichment and separation methods .The new microfluidic technology can accurately control the microliquid preciously , combined with the immunomagnetic separation technology , has been applied in detecting CTCs , which can save the blood samples of CTCs , has the advantages of simple operation , fast sorting speed , high specificity and high purity .

OBJECTIVE:To establish PCR reaction system of DNA of Marchantia convoluta in Guangxi marked with SCoT polymorphism marker technique by screening primer and optimizing reaction condition. METHODS:Modified CTAB method was used to extract DNA of M. convolute from Guangxi;gel electrophoresis and UV spectrophotometry were used to investigate purity and concentration of DNA. Using sample DNA as template,PCR amplification of 36 SCoT primers was conducted,and suitable primers were screened after electrophoresis,staining and imaging of products. The orthogonal experiment of 5 factors and 4 levels was conducted by 5 main factors as DNA concentration,Mg2 + concentration,dNTP concentration,primer concentration,Taq DNA polymerase concentration. The condition of SCoT-PCR reaction system was optimized. RESULTS:Extracted sample DNA bands were neat without RNA contamination,degradation or dispersion of fluorescence;sample well was clear. UV absorbance ratio ranged 1.7-2.0 at 260 nm and 280 nm;purity and concentration of DNA were both suitable for follow-up test. PCR results of 36 primers showed that product band of No. 4 primer was neat without diffuse fluorescence but with best luminance,so No. 4 primer was used for PCR reaction. The optimal SCoT-PCR reaction system contained 30.00 μg/mL DNA,2.00 mmol/L Mg2+,0.20 mmol/L dNTP, 0.40 μmol/L primer,0.50 U/mL Taq DNA polymerase(total reaction volume of 20 μL). CONCLUSIONS:Suitable SCoT-PCR primer of DNA is screened,and reaction system is optimized. It provides technologic basis for variety identification and genetic relationship analysis of M. convoluta in Guangxi.

The ATP-binding cassette (ABC) transporter superfamily comprises membrane proteins that efflux various substrates across extra- and intracellular membranes. Among them, ABCB1, ABCG2, and ABCC1 are directly linked to tumor multidrug resistance (MDR). This review provides an overview of the current understanding on the novel mechanisms and functions of ABCB1, ABCG2, and ABCC1 transporters in tumor MDR, discusses the latest strategies to target these transporters, and explores further opportunities to overcome MDR.