Detection of FAM172A expressed in circulating tumor cells is a feasible method to predict high-risk subgroups of colorectal cancer

Abstract

Previous studies used to enumerate circulating tumor cells to predict prognosis and therapeutic effect of colorectal cancer. However, increasing studies have shown that only circulating tumor cells enumeration was not enough to reflect the heterogeneous condition of tumor. In this study, we classified different metastatic-potential circulating tumor cells from colorectal cancer patients and measured FAM172A expression in circulating tumor cells to improve accuracy of clinical diagnosis and treatment of colorectal cancer. Blood samples were collected from 45 primary colorectal cancer patients. Circulating tumor cells were enriched by blood filtration using isolation by size of epithelial tumor cells, and in situ hybridization with RNA method was used to identify and discriminate subgroups of circulating tumor cells. Afterwards, FAM172A expression in individual circulating tumor cells was measured. Three circulating tumor cell subgroups (epithelial/ biophenotypic/mesenchymal circulating tumor cells) were identified using epithelial-mesenchymal transition markers. In our research, mesenchymal circulating tumor cells significantly increased along with tumor progression, development of distant metastasis, and vascular invasion. Furthermore, FAM172A expression rate in mesenchymal circulating tumor cells was significantly higher than that in epithelial circulating tumor cells, which suggested that FAM172A may correlate with malignant degree of tumor. This hypothesis was further verified by FAM172A expression in mesenchymal circulating tumor cells, which was strictly related to tumor aggressiveness factors. Mesenchymal circulating tumor cells and FAM172A detection may predict highrisk stage II colorectal cancer. Our research proved that circulating tumor cells were feasible surrogate samples to detect gene expression and could serve as a predictive biomarker for tumor evaluation.

The Effect of Protein FAM172A on Proliferation in HepG2 Cells and Investigation of the Possible Molecular Mechanism

“…In a study by Cui et al, FAM172A expression was associated with the malignant degree of the tumor which could be used to identify colorectal cancer patients with a more serious disease stage for appropriate early treatment. Cui et al has drawn a correlation between the circulating tumor cell positive rate and the FAM172A expression positive rate [31]. Another study by Li et al on the effect of the FAM172A protein on HEK293 cells demonstrated similar results.…”

<p>Common molecular markers between circulating tumor cells and blood exosomes in colorectal cancer: a systematic and analytical review</p>

“…After 2004, researchers focused on multi-marker panels in literature or data mining as listed in Table 2 49–56. Besides these, novel markers such as serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), SERPINB5,57 epidermal growth factor receptor (EGFR),58–60 epithelial cell transforming sequence 2 oncogene (ECT2)61 FAM172A,62 A3 receptor63 have been examined as well as other markers, especially through bioinformatics analysis 64Table 2The biomarkers which worked for diagnostic of CRC in circulating tumor cellsBiomarkerTechnique of isolation/detection of CTCTechnique of validation/related oneRelated markerCutoffPatients (number/type)Patient stageAuthor/ yearCTCs positive ratePMIDCK20Nested RT-PCR1SWI 116, HT29 cell spiking–5 mL57 patients, 2 controls2/BloodI–IV3Soeth, 1996 28…”

“…18%18,936,523ECT2Nested qPCR–CEA4 mL90 patients, 151controls/bloodI–IVChen, 2017 61–28,362,321FAM172AFiltrationIn situ hybridizationEpCAM, CK8, CK18, CK19, Vimentin, Twist, CD45 − .5mL45/BloodI–IVCui, 2017 6275.6%28,618,931A3 adenosine receptorsReal-time RT-PCRImmunocytochemistry–40 mL30/BloodI–IVGessi, 2003 63…”

Current progress in the clinical use of circulating tumor cells as prognostic biomarkers

“…57,58 It is anticipated that such techniques may be used for more sophisticated analysis based on specific markers, such as detection of the KRAS mutation in peripheral blood CTCs, which has been associated with response to cetuximab plus chemotherapy, 59 or FAM172A expression in mesenchymal CTCs, which may be predictive of high-risk stage II colorectal cancer. 60 CTC count has been reported to be predictive of metastasis in patients with gastric cancer, 54 which is a particularly aggressive cancer that is common in Asia, Eastern Europe, and Central and South America. Within the CTC population, gastric cancer CTCs with stem-like properties are considered to play a particular role in metastasis, and CD44-positive CTCs in patients with gastric cancer have been found to be predictive of both metastasis and disease recurrence.…”

“…Quantification of CTCs has been validated for colorectal cancer prognosis, and increasingly sensitive approaches are being developed for CTC detection in patients with colorectal cancer . It is anticipated that such techniques may be used for more sophisticated analysis based on specific markers, such as detection of the KRAS mutation in peripheral blood CTCs, which has been associated with response to cetuximab plus chemotherapy, or FAM172A expression in mesenchymal CTCs, which may be predictive of high‐risk stage II colorectal cancer …”