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Background: In an intercross between the SWR/J and BALB/c mouse strains, the pulmonary adenoma progression 1 (Papg1) locus on chromosome 4 modulates lung tumor size, one of several measures of lung tumor progression. This locus has not been fully characterized and defined in its extent and genetic content. Fine mapping of this and other loci affecting lung tumor phenotype is possible using recombinant inbred strains. Results: A population of 376 mice, obtained by crossing mice of the SWR/J strain with CXBN recombinant inbred mice, was treated with a single dose of urethane and assayed for multiplicity of large lung tumors (N2lung). A genome-wide analysis comparing N2lung with 6364 autosomal SNPs revealed multiple peaks of association. The Papg1 locus had two peaks, at rs3654162 (70.574 Mb, -logP=2.8) and rs6209043 (86.606 Mb, -logP=2.7), joined by an interval of weaker statistical association; these data confirm the presence of Papg1 on chromosome 4 and reduce the mapping region to two stretches of ~6.8 and ~4.2 Mb, in the proximal and distal peaks, respectively. The distal peak included Cdkn2a, a gene already proposed as being involved in Papg1 function. Other loci possibly modulating N2lung were detected on chromosomes 5, 8, 9, 11, 15, and 19, but analysis for linkage disequilibrium of these putative loci with Papg1 locus suggested that only those on chromosomes 11 and 15 were true positives. Conclusions: These findings suggest that Papg1 consists, most likely, of two distinct, nearby loci, and point to putative additional loci on chromosomes 11 and 15 modulating lung tumor size. Within Papg1, Cdkn2a appears to be a strong candidate gene while additional Papg1 genes await to be identified. Greater knowledge of the genetic and biochemical mechanisms underlying the germ-line modulation of lung tumor size in mice is relevant to other species, including humans, in that it may help identify new therapeutic targets in the fight against tumor progression. [ABSTRACT FROM AUTHOR]

Background: MFSD2A (major facilitator superfamily domain containing 2) gene maps on chromosome 1p34 within a linkage disequilibrium block containing genetic elements associated with progression of lung cancer. Results: Here we show that MFSD2A expression is strongly downregulated in non-small cell lung cancer cell lines of different histotypes and in primary lung adenocarcinomas. Experimental modulation of MFSD2A in lung cancer cells is associated with alteration of mRNA levels of genes involved in cell cycle control and interaction with the extracellular matrix. Exogenous expression of MFSD2A in lung cancer cells induced a G1 block, impaired adhesion and migration in vitro, and significantly reduced tumor colony number in vitro (4- to 27-fold, P < 0.0001) and tumor volume in vivo (∼3-fold, P < 0.0001). siRNA knockdown studies in normal human bronchial epithelial cells confirmed the role of MFSD2A in G1 regulation. Conclusion: Together these data suggest that MFSD2A is a novel lung cancer tumor suppressor gene that regulates cell cycle progression and matrix attachment. [ABSTRACT FROM AUTHOR]

An abstract of the article "MFSD2A is a novel lung tumour suppressor gene whose expression is modulated by a 5'-region polymorphism," by Francesca Colombo, Monica Spinola, and Felicia S Falvella is presented.

Background: The MFSD2A gene maps within a linkage disequilibrium block containing the MYCL1-EcoRI polymorphism associated with prognosis and survival in lung cancer patients. Survival discrepancies between Asians and Caucasians point to ethnic differences in allelic frequencies of the functional genetic variations., Results: Analysis of three single-nucleotide polymorphisms (SNPs) mapping in the MFSD2A 5'-regulatory region using a luciferase reporter system showed that SNP rs12072037, in linkage disequilibrium with the MYCL1-EcoRI polymorphism and polymorphic in Asians but not in Caucasians, modulated transcriptional activity of the MFSD2A promoter in cell lines expressing AHR and ARNT transcription factors, which potentially bind to the SNP site., Conclusion: SNP rs12072037 modulates MFSD2A promoter activity and thus might affect MFSD2A levels in normal lung and in lung tumors, representing a candidate ethnically specific genetic factor underlying the association between the MYCL1 locus and lung cancer patients' survival.

Background: MFSD2A (major facilitator superfamily domain containing 2) gene maps on chromosome 1p34 within a linkage disequilibrium block containing genetic elements associated with progression of lung cancer., Results: Here we show that MFSD2A expression is strongly downregulated in non-small cell lung cancer cell lines of different histotypes and in primary lung adenocarcinomas. Experimental modulation of MFSD2A in lung cancer cells is associated with alteration of mRNA levels of genes involved in cell cycle control and interaction with the extracellular matrix. Exogenous expression of MFSD2A in lung cancer cells induced a G1 block, impaired adhesion and migration in vitro, and significantly reduced tumor colony number in vitro (4- to 27-fold, P < 0.0001) and tumor volume in vivo (approximately 3-fold, P < 0.0001). siRNA knockdown studies in normal human bronchial epithelial cells confirmed the role of MFSD2A in G1 regulation., Conclusion: Together these data suggest that MFSD2A is a novel lung cancer tumor suppressor gene that regulates cell cycle progression and matrix attachment.