Identification of differential gene expressions in colorectal cancer and polyp by cDNA microarray

AIM： TO screen the differential expressed genes in colorectal cancer and polyp tissue samples. METHODS： Tissue specimens containing 16 cases of colorectal adenocarcinoma and colorectal polyp vs nor- mal mucosae were collected and subjected to cDNA microarray and bioinformatical analyses. Quantitative reverse transcription-polymerase chain reaction （qRT- PCR） was used to confirm some of the cDNA microarray data.RESULTS： The experimental data showed that eight genes were differentially expressed, most of which were upregulated in adenomatous polyp lesions. Forty-six genes expressions were altered in colorectal cancers, of which 29 were upregulated and 17 downregulated, as compared to the normal mucosae. In addition, 18 genes were similarly altered in both adenomatous polyps and colorectal cancer, qRT-PCR analyses confirmed the cDNA microarray data for four of those 18 genes： MTA1, PDCD4, TSC1 and PDGFRA. CONCLUSION： These differentially expressed genes likely represent biomarkers for early detection of co- Iorectal cancer and may be potential therapeutic targets after confirmed by further studies.

Improved mammalian family phylogeny using gap-rare multiple sequence alignment:A timetree of extant placentals and marsupials

The timing of mammalian diversification in relation to the Cretaceous-Paleogene(KPg)mass extinction continues to be a subject of substantial debate.Previous studies have either focused on limited taxonomic samples with available whole-genome data or relied on short sequence alignments coupled with extensive species samples.In the present study,we improved an existing dataset from the landmark study of Meredith et al.(2011)by filling in missing fragments and further generated another dataset containing 120 taxa and 98 exonic markers.Using these two datasets,we then constructed phylogenies for extant mammalian families,providing improved resolution of many conflicting relationships.Moreover,the timetrees generated,which were calibrated using appropriate molecular clock models and multiple fossil records,indicated that the interordinal diversification of placental mammals initiated before the Late Cretaceous period.Additionally,intraordinal diversification of both extant placental and marsupial lineages accelerated after the KPg boundary,supporting the hypothesis that the availability of numerous vacant ecological niches subsequent to the mass extinction event facilitated rapid diversification.Thus,our results support a scenario of placental radiation characterized by both basal cladogenesis and active interordinal divergences spanning from the Late Cretaceous into the Paleogene.