Single nucleotide polymorphisms (SNPs) may contribute to the malignant process and may show clinicopathological importance as prognostic markers. The multidrug resistance gene @entity1262 encodes a membrane transporter which confers cytostatic drug resistance in @entity5 and protects normal tissues from xenobiotics. We analyzed the @entity7658 SNP in the @entity1262 gene which is associated with altered cellular drug uptake in matched @entity5 and normal tissues of 45 @entity1 suffering from @entity14 . We have developed a highly sensitive matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF- @entity15 ) method to survey the @entity7658 polymorphism in PCR-amplified fragments of the @entity1262 gene. Thirteen @entity1 were homozygous for C/C (29%), 15 were heterozygous (33%) and 17 were homozygous for @entity1619 (38%). None of the @entity5 samples showed an altered SNP compared to their matched normal tissue samples. As analyzed by the Kruskall-Wallis test, none of the clinicopathological parameters was significantly associated with homo- or heterozygosity. The combination of PCR, allele-specific primer extension reactions and MALDI-TOF- @entity15 offers a promising alternative method for genotyping the @entity1262 gene especially for heterozygous situations. The inherent advantages of MALDI-TOF- @entity15 based genotyping include its high molecular resolution, high signal-to-noise-ratios and reproducibility, combined with an excellent sensitivity. As none of the @entity5 samples showed an altered state compared to their matched normal tissue samples, the genotypic frequency of this polymorphism seems not to be altered during colorectal tumorigenesis.

XXXX single nucleotide polymorphism @entity7658 in normal colorectal tissue and @entity14 detected by MALDI-TOF mass spectrometry.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1262 :: ('5243', 'Gene') :: ['MDR1'] @entity1619 :: ('MESH:D015458', 'Disease') :: ['T/T'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors'] @entity14 :: ('MESH:D015179', 'Disease') :: ['colorectal carcinoma'] @entity15 :: ('MESH:D009103', 'Disease') :: ['MS'] @entity7658 :: ('c|SUB|C|3435|T', 'DNAMutation') :: ['C3435T']
@entity1262 :: (5243,Gene) :: ['MDR1']
