Multidrug resistance markers P-glycoprotein, multidrug resistance protein 1, and lung resistance protein in non-small cell lung cancer: prognostic implications

Natural, agricultural and human populations are structured, with a proportion of interactions occurring locally or within social groups rather than at random. This within-population spatial and social structure is important to the evolution of parasites but little attention has been paid to how spatial structure affects the evolution of host resistance, and as a consequence the coevolutionary outcome. We examine the evolution of resistance across a range of mixing patterns using an approximate mathematical model and stochastic simulations. As reproduction becomes increasingly local, hosts are always selected to increase resistance. More localized transmission also selects for higher resistance, but only if reproduction is also predominantly local. If the hosts disperse, lower resistance evolves as transmission becomes more local. These effects can be understood as a combination of genetic (kin) and ecological structuring on individual fitness. When hosts and parasites coevolve, local interactions select for hosts with high defence and parasites with low transmissibility and virulence. Crucially, this means that more population mixing may lead to the evolution of both fast-transmitting highly virulent parasites and reduced resistance in the host

Whole genome amplification for CGH analysis: Linker-adapter PCR as the method of choice for difficult and limited samples.

Background Comparative genomic hybridization (CGH) is a powerful method to investigate chromosomal imbalances in tumor cells. However, DNA quantity and quality can be limiting factors for successful CGH analysis. The aim of this study was to investigate the applicability of degenerate oligonucleotide-primed PCR (DOP-PCR) and a recently developed linker-adapter-mediated PCR (LA-PCR) for whole genome amplification for use in CGH, especially for difficult source material. Methods We comparatively analyzed DNA of variable quality derived from different cell/tissue types. Additionally, dilution experiments down to the DNA content of a single cell were performed. FISH and/or classical cytogenetic analyses were used as controls. Results In the case of high quality DNA samples, both methods were equally suitable for CGH. When analyzing very small amounts of these DNA samples (equivalent to one or a few human diploid cells), DOP-PCR-CGH, but not LA-PCR-CGH, frequently produced false-positive signals (e.g., gains in 1p and 16p, and losses in chromosome 4q). In case of formalin-fixed paraffin-embedded tissues, success rates by LA-PCR-CGH were significantly higher as compared to DOP-PCR-CGH. DNA of minor quality frequently could be analyzed correctly by LA-PCR-CGH, but was prone to give false-positive and/or false-negative results by DOP-PCR-CGH. Conclusions LA-PCR is superior to DOP-PCR for amplification of DNA for CGH analysis, especially in the case of very limited or partly degraded source material