Improved real-time rt-PCR assays of two colorectal cancer peripheral blood mRNA biomarkers: a pilot study

Liquid Biopsy-Based Colorectal Cancer Screening via Surface Markers of Circulating Tumor Cells

Colorectal cancer (CRC) is ranked second for cancer-related deaths worldwide with approximately half of the patients being diagnosed at the late stages. The untimely detection of CRC results in advancement to the metastatic stage and nearly 90% of cancer-related deaths. The early detection of CRC is crucial to decrease its overall incidence and mortality rates. The recent introduction of circulating tumor cells (CTCs) has enabled a less invasive sampling method from liquid biopsies, besides revealing key information toward CRC metastasis. The current gold standard for CTC identification is the CellSearch® system (Veridex). This first-generation instrumentation relies on a single cell surface marker (CSM) to capture and count CTCs. Detection of CTCs allows the identification of patients at risk for metastasis, whereas CTC enumeration could improve risk assessment, monitoring of systemic therapy, and detection of therapy resistance in advanced metastatic CRC. In this review, we compared the pros and cons between single CSM-based CTC enrichment techniques and multi-marker-based systems. We also highlighted the challenges faced in the routine implementation of CSM-dependent CTC detection methods in CRC screening, prediction, prognosis, disease monitoring, and therapy selection toward precision medicine, as well as the dwelling on post-CTC analysis and characterization methods.

Melanoma antigen-encoding gene family member A1-6 and hTERT in the detection of circulating tumor cells following CD45- depletion and RNA extraction

A total of 76 blood samples from patients without malignant disease and 107 blood samples from patients with malignant disease were investigated for the presence of circulating tumor cells (CTCs). To detect CTCs, hematopoietic cells were removed from the blood samples and different RNA extraction methods were used to amplify the melanoma antigen-encoding gene family member A1-family member A6 (MAGE A1-6) and the human telomerase reverse transcriptase (hTERT) gene as potential CTC markers. Comparison between four methods for extracting RNA from the blood was performed. The samples were enriched by cluster of differentiation 45 (CD45) antibody capturing, and the reverse transcription-quantitative polymerase chain reaction was used to amplify the MAGE A1-6 and hTERT genes. MAGE A1-6 and hTERT gene expression levels were also evaluated in 14 cancer cell lines, and the MAGE A1-6 and hTERT expression levels were 85.7 and 100%, respectively. The RNeasy method demonstrated the most sensitivity in the SNU1 cells mixed with blood, although the differences between methods was non-significant. The positive expression levels of MAGE A1-6 and hTERT was 11.8% in the control group and 58.9% in those with malignant disease. In the 70 patients with colorectal cancer, positive expression levels of MAGE A1-6 or hTERT were significantly higher in stages T3 and T4 compared with in stages T1 and T2. The CTC detection method involving CD45 antibody capture, RNA extraction and MAGE A1-6 and hTERT reverse transcription resulted in good rates of sensitivity and specificity. Thus, the present study concluded that MAGE A1-6 and hTERT genes may be potential and practical markers for CTCs in a clinical setting.

A Pilot Study of CK19, CK20 and GCC mRNA in the Peripheral Blood as a Colorectal Cancer Biomarker Panel

Colorectal cancer remains one of the major cancer- related deaths despite progress in the treatment during past decades. Detection of disease at earlier stages reduces its mortality. The aim of current study was to investigate expression of Cytokeratin 19 (CK19), Cytokeratin 20 (CK20) and Guanylyl Cyclase C (GCC) mRNA in peripheral blood of non- metastatic colorectal cancer patients which may result into introducing of an early detection test. 25 patients with colorectal cancer and 25 healthy controls were recruited. Blood was obtained from all individuals. Expression of CK19 and CK20 and GCC mRNA and 18SrRNA (as reference gene) were determined based on real- time RT-PCR on total RNA from blood. CK19, CK20 and GCC expression had been detected in 68%, 76% & 52% of patient group, respectively, which was higher than healthy group, with 8%, 32% and 0% expression, respectively (p<0.05). CK20 was over-expressed 8- fold more in patients compared to controls. Similar result was found for CK19 with 4- fold over- expression. Sensitivity and specificity of combination of markers were 88% and 68%, respectively. Current data suggest that the detection of CK20 & CK19 as relative sensitive markers may become a valuable tool for primary diagnosis of colorectal cancer in early stages. GCC could be considered as a specific tumor marker for detection of colorectal cancer. Higher expression of these markers in patients may be considered as a relative good tool for the diagnosis of disease in non- metastatic stages.

A brief review on long noncoding RNAs: a new paradigm in breast cancer pathogenesis, diagnosis and therapy

With the development of technologies such as microarrays and RNA deep sequencing, long noncoding RNAs (lncRNAs) have become the focus of cancer investigations. LncRNAs, nonprotein-coding RNA molecules longer than 200 nucleotides, are dysregulated in many human diseases, especially in cancers. Recent studies have demonstrated that lncRNAs play a key regulatory role in gene expression and cancer biology through diverse mechanisms, including chromosome remodeling and transcriptional and post-transcriptional modifications. The expression levels of specific lncRNAs are attributed to prognosis, metastasis, and recurrence of cancer. LncRNAs are often involved in various biological processes, such as regulation of alternative splicing of mRNA, protein activity, and epigenetic modulation or silencing of the microRNAs, via discrete mechanisms. Deregulated levels of lncRNAs are shown in diverse tumors, including breast cancer. Based on latest research data, the tissue-specific expression signature of lncRNAs may represent the potential to discriminate normal and tumor tissue or even the different stages of breast cancer, which makes them clinically beneficial as possible biomarkers in the diagnosis and prognosis or therapeutic targets. In this brief review, we summarize some recent researches in the context of lncRNAs' roles in breast cancer pathogenesis and their potential to serve as diagnostic, predictive, and prognostic biomarkers and novel targets for breast cancer treatment.

Expression of two basic mRNA biomarkers in peripheral blood of patients with non-small cell lung cancer detected by real-time rt-PCR, individually and simultaneously

Introduction: Although extensive research has been conducted on lung cancer markers, a singular clinically applicable marker has not been found yet. The objective of this study was to evaluate the sensitivity and the specificity of carcinoembryonic antigen (CEA) mRNA and lung-specific X protein (LUNX) mRNA biomarkers in peripheral blood to detect lung cancer individually and simultaneously. Methods: Thirty patients affected by lung cancer and 30 healthy individuals were studied in this research. Three vials of cDNA were made from each sample after taking peripheral blood samples and extracting total RNA. Each sample was examined by the real-time RT-PCR technique. The result from each vial was then compared with the sensitivity of overall marker. Results: The CEA mRNA was positive in 24 out of 30 lung cancer patients. Hence, its sensitivity was determined at 80%, differing significantly from that observed in healthy individuals, where 11 positive cases were seen. The overall sensitivity of this marker was significantly associated with positivity in vials 2 and 3 but not in vial 1. The LUNX mRNA was positive in 21 out of 30 patients, indicating 70% sensitivity. This finding significantly differed from that in healthy individuals. The overall sensitivity of this marker was significantly associated with positivity in vials 1 and 3, but not in vial 2. In 93.3% of the patients, at least one positive marker was observed. Conclusion: The mentioned mRNA could be suggested as sensitive and specific markers in peripheral blood for primary diagnosis of lung cancer.

Expression Analysis of mir-21 and mir-221 in Cancerous Tissues from Iranian Patients with Gastric Cancer

BACKGROUND

Early detection is a key to survival for gastric cancer. Molecular markers such as miRNA (microRNA) can have great importance in the early diagnosis of gastric cancer. Expression of miR-21 and miR-221 are deregulated in many types of human cancers. This study aimed to investigate the differences in miRNA expression patterns within the Iranian population.

METHODS

Total RNA was extracted from gastric cancer tissues and adjacent non-cancerous tissues from 32 patients. Expression levels of miR-21 and miR-221 were detected by Real time RT-PCR using a specific primer, with 5s rRNA as the internal reference gene.

RESULTS

Our data showed that the expression levels of miR-21 and miR-221 in gastric cancer samples were significantly higher than in paired non-cancerous samples (P value less than 0.05). The receiver operating characteristic (ROC) analyses yielded the area under the curve (AUC) values of 80.30 for miR-21 and 93.30 for miR-221, and combined ROC analysis revealed the highest AUC value of 96.90 in discriminating GC patients from healthy controls.

CONCLUSION

It seems that miR-21 and miR-221 expression pattern in Iranian patients with gastric cancer are similar to any other population. Considering the increased expression level of two miRNAs in cancerous tissue compared to normal tissue as well as the area under ROC curve, miR-21 and miR-221 can be used for early detection of gastric cancer.