Whole blood ACTB, B2M and GAPDH expression reflects activity of inflammatory bowel disease, advancement of colorectal cancer, and correlates with circulating inflammatory and angiogenic factors: Relevance for real-time quantitative PCR

BACKGROUND

The effect of bowel inflammation and cancer on the expression of the most prevalent internal controls: ACTB, GAPDH and B2M in whole blood is unknown, although at least GAPDH occurred to be tightly regulated and suspected of supporting cancer growth, challenging its suitability as a reference.

OBJECTIVES

To evaluate the effect of colorectal cancer (CRC) and active inflammatory bowel disease (IBD) on the stability of ACTB, B2M, GAPDH, HPRT1, SDHA, and TBP leukocyte expression.

MATERIAL AND METHODS

Gene expression in controls and CRC and IBD patients (n = 21/18/25) was evaluated in real-time quantitative polymerase chain reaction (RT-qPCR) using NormFinder, geNorm, BestKeeper, and comparative ΔCt method, and validated by comparison with absolute quantification of interleukin 1β (IL-1β) and CCL4.

RESULTS

HPRT1, SDHA and TBP were superior normalizers in CRC and IBD. The highest expression variability was noted in active IBD. B2M was significantly lower in CRC but higher in IBD. GAPDH was higher in CRC and IBD. ACTB and GAPDH corresponded with CRC advancement (ρ = 0.52 and ρ = 0.53) and with clinical activity in Crohn's disease (ρ = 0.44 and ρ = 0.57) and ulcerative colitis (GAPDH: ρ = 0.72). ACTB, B2M and GAPDH correlated with circulating inflammatory/angiogenic indices, differently in IBD and CRC.

CONCLUSIONS

Leukocyte GAPDH, ACTB, and B2M expression is affected by bowel inflammation and cancer, rendering them unsuitable as a reference in CRC and IBD.

Detecting fetal DNA from dried maternal blood spots: another step towards broad scale non-invasive prenatal genetic screening and feasible testing

Both intact fetal cells and cell-free fetal DNA are present in the maternal circulation and have been used for non-invasive prenatal genetic diagnosis. However, broad clinical application awaits development of robust methods for collecting, transporting and enriching maternal blood samples to recover rare fetal cells. To circumvent this impediment, we have devised a reliable method of fetal DNA detection using dried maternal blood spots and real-time polymerase chain reaction. Fetal Y-specific (DYS1) sequences were detected in all 19 (100%) maternal blood specimens from women carrying male fetuses, in genome equivalents of 4.20-24.68 per ml of blood; the ubiquitous glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene, reflecting both maternal and fetal DNA, concurrently showed 43,684 to 680,357 genome equivalents per ml of blood. The results demonstrate that fetal DNA detection using dried maternal blood spots is highly feasible and easily adaptable for population screening.