Radical radiotherapy for locally advanced non-small cell lung cancer-what's up with arm positioning?

Radical thoracic radiotherapy is ideally delivered in the arms-up (AU) position; however, patient comfort may only allow for arms-down (AD) positioning to be feasible. Objectives of this study were (I) to evaluate the dosimetric impact of changing arm position during treatment and (II) to compare plan quality for optimization in AU AD positions. In this retrospective planning study, stage III lung cancer patients (n=10) who received 60 Gy in 30 fractions using volumetric modulated arc therapy (VMAT) were identified.

Changes in cobalamin metabolism are associated with the altered methionine auxotrophy of highly growth autonomous human melanoma cells.

Our aim was to identify the biochemical defect responsible for the inability of highly growth autonomous human tumor cells to proliferate in culture medium devoid of methionine, but containing homocysteine and 5-methyletrahydrofolic acid. We have adopted the terms "homocysteine-responsive" and "homocysteine-nonresponsive" to describe cells which can or cannot proliferate in methionine-free homocysteine-supplemented medium. Using a panel of genetically related homocysteine-responsive and -nonresponsive human melanoma cell lines, the results from a number of experiments indicate that acquisition of the "homocysteine-nonresponsive phenotype" is associated with the reduced intracellular accumulation of methyl-cobalamin, a critical cofactor of the methionine synthase enzyme.

Agarose-selected variants of two human tumor cell lines exhibit altered methionine auxotrophy.

Our aim was to determine if the selection of human tumor cells with enhanced anchorage-independent growth capacity was associated with alterations in methionine auxotrophy. Cells with an increased ability to form colonies on soft agarose were selected from human melanoma (MeWo) and neuroepithelioma (SK-N-MC) cell lines. In contrast to their respective parental lines, a high proportion of the agarose-selected variants were completely unable to proliferate in methionine-free medium containing its immediate precursor homocysteine.