The Lack of Evidence for an Association between Cancer Biomarker Conversion Patterns and CTC-Status in Patients with Metastatic Breast Cancer

Circulating Tumor Cells: Pathological, Molecular and Functional Characteristics

This Special Issue, 'Circulating Tumor Cells: Pathological, Molecular and Functional Characteristics 1 [...].

Research progress of CTC, ctDNA, and EVs in cancer liquid biopsy

Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vehicles (EVs) have received significant attention in recent times as emerging biomarkers and subjects of transformational studies. The three main branches of liquid biopsy have evolved from the three primary tumor liquid biopsy detection targets-CTC, ctDNA, and EVs-each with distinct benefits. CTCs are derived from circulating cancer cells from the original tumor or metastases and may display global features of the tumor. ctDNA has been extensively analyzed and has been used to aid in the diagnosis, treatment, and prognosis of neoplastic diseases. EVs contain tumor-derived material such as DNA, RNA, proteins, lipids, sugar structures, and metabolites. The three provide different detection contents but have strong complementarity to a certain extent. Even though they have already been employed in several clinical trials, the clinical utility of three biomarkers is still being studied, with promising initial findings. This review thoroughly overviews established and emerging technologies for the isolation, characterization, and content detection of CTC, ctDNA, and EVs. Also discussed were the most recent developments in the study of potential liquid biopsy biomarkers for cancer diagnosis, therapeutic monitoring, and prognosis prediction. These included CTC, ctDNA, and EVs. Finally, the potential and challenges of employing liquid biopsy based on CTC, ctDNA, and EVs for precision medicine were evaluated.

Association of survivin positive circulating tumor cell levels with immune escape and prognosis of osteosarcoma

PURPOSE

Function of survivin protein (encoded by BIRC5) in circulating tumor cells (CTCs) of osteosarcoma (OS) has not been investigated. The goal of this study is to determine whether the expression of survivin protein of CTCs is associated with circulating immune cell infiltration and disease prognosis of OS.

METHODS

Blood samples of 20 patients with OS were collected. CanPatrol™ CTC enrichment technology combined with in situ hybridization (ISH) was applied to enrich and test CTCs and survivin protein. Bioinformation analysis combined with data of routine blood test was used to verify the association between survivin and immune cell infiltration in circulatory system. To screen independent prognostic factors, Kaplan-Meier survival curve, univariate and multivariable Cox regression analyses were performed.

RESULTS

Bioinformatics analysis showed that BIRC5 was strongly negatively related to lymphocyte, including T cell, NK cell and B cell, which released that BIRC5 played a key role in immune escape via reducing immune cell infiltration in circulatory system. Meanwhile, the number of survivin+ CTCs was significantly negatively connection with lymphocyte count (R = -0.56, p = 0.011), which was consistent with bioinformatics analysis. Kaplan-Meier curve showed that the overall survival rate in high survivin+ CTCs group was significantly lower than low group (88.9% vs 36.4%, p = 0.04). Multivariable Cox regression analyses showed that survivin+ CTCs were an independent prognostic factor (p = 0.019).

CONCLUSION

These findings suggested that survivin protein played a key role in immune escape of CTCs and the presence of survivin+ CTCs might be a promising prognostic factor in OS patients.

Circulating tumor cells: biology and clinical significance

Circulating tumor cells (CTCs) are tumor cells that have sloughed off the primary tumor and extravasate into and circulate in the blood. Understanding of the metastatic cascade of CTCs has tremendous potential for the identification of targets against cancer metastasis. Detecting these very rare CTCs among the massive blood cells is challenging. However, emerging technologies for CTCs detection have profoundly contributed to deepening investigation into the biology of CTCs and have facilitated their clinical application. Current technologies for the detection of CTCs are summarized herein, together with their advantages and disadvantages. The detection of CTCs is usually dependent on molecular markers, with the epithelial cell adhesion molecule being the most widely used, although molecular markers vary between different types of cancer. Properties associated with epithelial-to-mesenchymal transition and stemness have been identified in CTCs, indicating their increased metastatic capacity. Only a small proportion of CTCs can survive and eventually initiate metastases, suggesting that an interaction and modulation between CTCs and the hostile blood microenvironment is essential for CTC metastasis. Single-cell sequencing of CTCs has been extensively investigated, and has enabled researchers to reveal the genome and transcriptome of CTCs. Herein, we also review the clinical applications of CTCs, especially for monitoring response to cancer treatment and in evaluating prognosis. Hence, CTCs have and will continue to contribute to providing significant insights into metastatic processes and will open new avenues for useful clinical applications.

Clinical utility of liquid biopsy in breast cancer: A systematic review

Advancements in genetic sequencing techniques along with the identification of specific mutations and structural changes in multiple cancer genes, make it possible to identify circulating tumor cells and cell free nucleic acids as blood-based biomarkers, serving as a liquid biopsy (LB) with great utility for the diagnosis, treatment and follow-up of patients with neoplasms. This systematic review focuses on the clinical utility of LB in patients with breast cancer (BC). Articles published between 1990 and 2021 were included. Databases searched: Trip Database, WoS, EMBASE, PubMed, SCOPUS, and Clinical Keys. Variables studied: Publication year, country, number of cases, primary study design, LB detection methods, genes found, overall survival, disease-free survival, stage, response to treatment, clinical utility, BC molecular type, systemic treatment and methodological quality of primary studies. Of 2619 articles, 74 were retained representing 12 658 patients, mainly cohort studies (66.2%), the majority were from China (15%) and Japan (12.2%). All primary studies described clinical stage and type of systemic treatment used. Most used biomarker detection method: DNA (52.7%) and type of analysis: quantification of total cfDNA (35.1%). PIK3CA mutation was most frequent (62.9%). Evidence suggests clinically useful applications of BC. Though heterogeneous, publications suggest that LB will constitute part of the standard diagnostic-therapeutic process of BC.

MRPL13 Promotes Tumor Cell Proliferation, Migration and EMT Process in Breast Cancer Through the PI3K-AKT-mTOR Pathway

Purpose

Breast cancer (BC), with varying histopathology, biology and response to systemic treatment, is the second leading cause of cancer-related mortality. Previous studies have inferred that the expression of mitochondrial ribosomal proteins (MRPs) is possibly related to the occurrence/progression of BC. MRPL13 might be one of the potential MRP candidates that are involved in BC tumorigenesis, but its role in BC has rarely been reported. The purpose of the current study was to evaluate the prognostic significance of MRPL13, as well as to explore its potential biological functions in BC.

Materials and Methods

A series of bioinformatic and statistical methods were adopted to assess the MRPL13 expression profile, its relationship with clinicopathological characteristics, copy number variation (CNV), impact on clinical outcomes and relevant functions. All the results are analysed by 1097 BC patients collected from The Cancer Genome Atlas (TCGA) dataset and 52 clinical samples for immunohistochemistry (IHC) assay.

Results

The results demonstrated that the expression of MRPL13 in BC tissues was remarkably elevated than that in normal breast tissues. In addition, the Kaplan-Meier curves and Cox model indicated that patients with high MRPL13 expression were connected to a worse prognosis, heralding the independent prognostic value of this protein in BC. Moreover, an enrichment analysis showed that MRPL13 was mainly involved in cell cycle/division-related, RNA processing (degradation/splicing), MYC targets and the MTORC1 pathways. In addition, RNA interference (RNAi)-mediated MRPL13 silencing remarkedly inhibited proliferation and migration as well as the expression of EMT-related genes of BC cells in vitro. Mechanistically, attenuation of MRPL13 significantly suppressed the phosphorylation of AKT and mTOR, which could be partially abolished by 740Y-P (a PI3K agonist).

Conclusion

Our results provide evidence for the first time that increased MRPL13 expression correlates with adverse clinicopathological variables and unfavorable clinical outcomes of BC patients. Knockdown of MRPL13 restrains the proliferation and migration potential and EMT process of BC through inhibiting PI3K/AKT/mTOR signaling pathway.