Overexpression of multidrug resistance gene, (MDR1) is responsible for the resistance of anticancer agents in cancer cells. In this study, we designed three pairs of DNA primers to clone MDR, cDNA from human normal liver by polymerase chain reaction. The sites of these primers in MDR cDNA are (I)-64-46 (5') and 1680-1698 (3'); (II) 1471-1489 (5') and 2905-2923 (3'); (III)2729-2747 (5') and 3845-3863 (3). The three reactions were underwent after the human normal liver mRNA was reverse transcripted into single strand DNA. The lengths of PCR products are 1762bp, 1452 bp and 1134bp, respectively. The former two products were subcloned in pBluscript SK, respectively and the latter product was subcloned in pGEM7Z (named as pMDR1.7, pMDR1.4 and pMDRl.l, respectively). Cloned genes were certificated as MDR1 cDNA by sequence analysis. Full-length MDR, cDNA was obtained after further subcloning. Full-length MDR1 cDNA we obtained will be a very important tool in molecular diagnosis and gene therapy of anticancer drug resistance.

Objective To look for mutations of the p53 gene in leukimic patients and study the relationship between abnormalities in p53 gene and leukemogenesis.Methods The peripheral blood and Bone Marrow Samples were collected from 36 patients with various leukemia types including 14 cases of lymphocytic leukemia [8 cases of acute lymphocytic leukemia (ALL), 4 cases of chronic lymphocytic leukemia (CLL), 2 cases of hairy cell leukemia (HCL)] and 22 cases of myelocytic leukemia [11 cases of acute non-lymphocytic leukemia (ANLL), 11 cases of chronic myelocytic leukemia (CML)]. DNA structures of exon 5-8 of the p53 gene were scanned by PCR-SSCP (single strand conformation polymorphism analysis of polymerase chain reaction products). The appropriate DNA fragments were amplified, Purified and sequenced directly.Results By PCR-SSCP analysis, shifts in electrophoretic mobility of the p53 gene were detected in 3 of 14 patients with lymphocytic leukemia (2 ALL and 1 CLL), but none in 22 patients with myelocytic leukemia including one in blastic crisis. Direct nucleotide sequencing in one patient with ALL showed transition of CTG to CAG at codon 257 of exon 7, resulting in a change of its encoded amino acids from aspartic acid to valine. To our knowledge, the mutation at this codon has not been previously reported hitherto.Conclusions The p53 gene mutations are specifically associated with lymphocytic leukemia. Alternations of the p53 gene may play a certain role in leukemogenesis in some cases of lymphocytic leukemia.

We have cloned full-length MDR1 cDNA from human normal liver tissue in previous study. Using this MDR1 cDNA as probe, we observed the MDR1 gene expression in human hepatocellular carcinoma treated with and without chemotherapy by Northern blot. The results showed that expression of MDR1 gene in hepatocellular carcinoma tissues was higher than that in their adjacent normal liver tissues; and enhanced MDR1 gene expression was also observed in hepatocellular carcinoma treated with chemotherapic agents. We also explored a method for quantitative analysis of MDR1 gene expression in hepatocellular carcinoma by polymerase chain reaction. This study suggests that overexpression of MDR1 gene may be responsible for the intrinsic and acquired drug resistance of human hepatocellular carcinoma, and PCR is a preferable method for quantitative analysis of MDR1 gene expression in hepatocellular carcinoma.

Objective:To analyze the expression of SMARCE1 in clear cell meningioma (CCM), and evaluate the role of SMARCE1 in the differential diagnosis in morphologically similar diseases.Methods:Thirteen samples/11 cases of CCMs were collected from the First Affiliated Hospital of Fujian Medical University, Shandong Provincial Hospital, Xuanwu Hospital of Capital Medical University and Thaihe Hospital of Hubei Province from January 2000 to December 2018, as well as 17 cases of meningiomas with clear-cell-like morphology, 782 cases of other types of meningiomas and other intracranial tumors with clear-like morphology. A tissue microarray was made using these cases, on which immunohistochemical/histochemical staining of SMARCE1, SSTR2, EMA, Ki-67, p53, PAS and D-PAS were performed.Result:The tumor cells of CCM had sheet-like architecture, without typical whorl formation.The CCM had round to polygonal cells, with clear, glycogen-rich cytoplasm and prominent blocky perivascular and interstitial collagen. The immunohistochemistry staining showed that none of the CCMs expressed SMARCE1(0/13).However, all of the other types of lesions, including meningioma(782/782), meningiomas with clear-like morphology(17/17), intracranial metastatic clear cell renal cell carcinoma(10/10), haemangioblastoma(10/10), central neurocytoma(10/10), oligodendroglioma(10/10), ependymoma(13/13), lioblastoma(42/42), and solitary fibrous tumor/hemangiopericytoma(35/35) showed positive nuclear staining of SMARCE1. Ki-67 index were 1%-5%, and p53 positive-rate were 0-40% in CCMs. PAS stain showed cytoplasmic granular positive and D-PAS were negative in all CCMs and meningiomas with clear-like morphology.Conclusion:SMARCE1 is a useful marker for the diagnosis of CCM and its mimickers.