Droplet digital PCR is the most robust method for absolute nucleic acid quantification. However, RNA is a very versatile molecule and its abundance is tissue-dependent. RNA quantification is dependent on a reference control to estimate the abundance. Additionally, in cancer, many cellular processes are deregulated which consequently affects the gene expression profiles. In this work, we performed microarray data mining of different childhood cancers and healthy controls. We selected four genes that showed no gene expression variations (PSMB6, PGGT1B, UBQLN2 and UQCR2) and four classical reference genes (ACTB, GAPDH, RPL4 and RPS18). Gene expression was validated in 40 acute lymphoblastic leukemia samples by means of droplet digital PCR. We observed that PSMB6, PGGT1B, UBQLN2 and UQCR2 were expressed ~100 times less than ACTB, GAPDH, RPL4 and RPS18. However, we observed excellent correlations among the new reference genes (p < 0.0001). We propose that PSMB6, PGGT1B, UBQLN2 and UQCR2 are housekeeping genes with low expression in childhood cancer.

Background B‐cell acute lymphoblastic leukemia (B‐ALL) is the most commonly diagnosed childhood malignancy worldwide and is especially common in Mexico. Additionally, the number of cases has increased in recent years. Thus, it is very important to develop molecular strategies to diagnose leukemia. The aim of this study was to investigate MYB expression and to determine its impact on the diagnosis of B‐ALL. Methods We analyzed the B‐ALL gene expression profile by microarray data mining. Bioinformatics analysis was performed to identify the genes that are overexpressed in leukemia. We determined that MYB was highly expressed in leukemia. Then, we validated MYB expression in 70 patients with B‐ALL and in 16 healthy controls (HCs) using qRT‐PCR. The results were statistically analyzed using the Kolmogorov‐Smirnov Z test, Mann‐Whitney U test, receiver operating characteristic curves, and the Youden index. Results The microarrays showed that MYB was overexpressed in B‐ALL patients with a fold change of 57.8728 and a P value of 2.56−195. MYB expression showed great variability among the patients analyzed. However, compared to the HCs, the B‐ALL patients had a P value < .0001, an area under the curve of 0.813, and a Youden index of 1.46, indicating the statistical significance. Conclusion MYB expression in B‐ALL cells could be a potential molecular marker for childhood leukemia.