Folic-acid metabolism and DNA-repair phenotypes differ between neuroendocrine lung tumors and associate with aggressive subtypes, therapy resistance and outcome

Abstract

Purpose25% of all lung cancer cases are neuroendocrine (NELC) including typical (TC) and atypical carcinoid (AC), large-cell neuroendocrine (LCNEC) and small cell lung cancer (SCLC). Prognostic and predictive biomarkers are lacking.Experimental DesignSixty patients were used for nCounter mRNA expression analysis of the folic-acid metabolism (ATIC, DHFR, FOLR1, FPGS, GART, GGT1, SLC19A1, TYMS) and DNA-repair (ERCC1, MLH1, MSH2, MSH6, XRCC1). Phenotypic classification classified tumors (either below or above the median expression level) with respect to the folic acid metabolism or DNA repair.ResultsExpression of FOLR1, FPGS, MLH1 and TYMS (each p<0.0001) differed significantly between all four tumor types. FOLR1 and FPGS associated with tumor differentiation (both p<0.0001), spread to regional lymph nodes (FOLR1 p=0.0001 and FPGS p=0.0038), OS and PFS (FOLR1 p<0.0050 for both and FPGS p<0.0004 for OS).Phenotypic sorting revealed the Ft-phenotype to be the most prominent expression profile in carcinoids, whereas SCLC presented nearly univocal with the fT and LCNEC with fT or ft. These results were significant for tumor subtype (p<0.0001).ConclusionsThe assessed biomarkers and phenotypes allow for risk stratification (OS, PFS), diagnostic classification and enhance the biological understanding of the different subtypes of neuroendocrine tumors revealing potential new therapy options and clarifying known resistance mechanisms.

ACTB, CDKN1B, GAPDH, GRB2, RHOA and SDCBP Were Identified as Reference Genes in Neuroendocrine Lung Cancer via the nCounter Technology

“…ACTB and GAPDH were detectable in 100% of cases and the remaining genes were detected in all but one case. As control, the coefficient of determination was also calculated for the reference genes and tumor markers CDK6 [15] and TYMS [14] and showed considerably low correlations between them.…”

“…Three to five paraffin sections with a thickness of 4 μm per sample were deparaffinized with xylene prior to RNA extraction using the RNeasy FFPE kit (Qiagen, Hilden, Germany) according to the manufacturer’s recommendations with slight adjustments as described earlier [14, 15]. Total RNA concentrations were measured using a Nanodrop 1000 instrument (Thermo Fisher Scientific, Waltham, USA) and an Agilent 2100 Bioanalyzer (eukaryote total RNA Nano, version 2.6, Agilent Technologies, Santa Clara, USA).…”

“…The CodeSet was designed to contain a total of 91 genes with different signature genes for each subgroup as described elsewhere [7, 14–16]. The CodeSet was designed and synthesized at NanoString Technologies, Seattle, USA (S1 Table for properties of the CodeSet).…”

“…Scatterplots were generated and coefficients of determination (R 2 ) were calculated for pairwise comparison of potential reference genes. As control, two previously identified tumor markers ( CDK6 and TYMS [14, 15]) were correlated with the reference genes as described above.…”

Blood folic acid, vitamin B12, and homocysteine levels in pregnant women with fetal growth restriction

“…Moreover, long-term effects of FGR include growth retardation (Chia and Huang, 2014), developmental anomalies (Streimish et al, 2012), congenital anomalies (Clausson et al, 1999), cardiovascular diseases (Khadilkar and Parthasarathy, 2015), ischemia anoxic encephalopathy (Kovo et al, 2015), chronic lung diseases (Bose et al, 2009), gastrointestinal diseases (Liu et al, 2014), kidney diseases (Ojeda et al, 2008), and endocrine metabolic disorders (Sánchez-Vera et al, 2005). Folic acid (FA) (Walter et al, 2016) and Vitamin B12 (Vit B12) (O'Leary and Samman, 2010) are mainly obtained through diet, and are important coenzymes for DNA synthesis. The fetus requires high levels of FA and Vit B12, especially during late pregnancy.…”