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.

@entity1262 single nucleotide polymorphism XXXX 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']
@entity7658 :: (c|SUB|C|3435|T,DNAMutation) :: ['C3435T']
