As the current staging and grading systems are not sufficient to stratify patients for therapy and predict the outcome of the disease, there is an urgent need to understand cancer in its complexity. The mutual relationship between tumour and immune or stromal cells leads to rapid evolution and subsequent genetic and epigenetic changes. Immunoscore has been introduced as a diagnostic tool for colorectal cancer (CRC) only recently, emphasising the role of the specific tumor microenvironment in patient’s prognosis and overall outcome. Despite the fact that non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), cannot be translated into proteins, they significantly affect cell’s transcriptome and translatome. miRNA binding to mRNA efficiently blocks its translation and leads to mRNA destruction. On the other hand, miRNAs can be bound by lncRNAs or circular RNAs (circRNAs), which prevents them from interfering with translation. In this way, ncRNAs create a multi-step network that regulates the cell’s translatome. ncRNAs are also shed by the cell as exogenous RNAs and they are also found in exosomes, suggesting their role in intercellular communication. Hence, these mechanisms affect the tumor microenvironment as much as protein signal molecules. In this review, we provide an insight into the current knowledge of the microenvironment, lncRNAs’, and miRNAs’ interplay. Understanding mechanisms that underlie the evolution of a tissue as complex as a tumour is crucial for the future success in therapy.

As the second most deadly cancerous disease worldwide, colorectal cancer (CRC) stands in the center of scientific interest in hope to develop novel approaches for precise diagnostics and prognosis determination. Metastatic disease remains the main cause of CRC mortality. To investigate the underlying genetic differences between CRC patients with synchronous and metachronous liver metastases, we performed whole‐exome sequencing of 210 patient samples using formalin‐fixed paraffin‐embedded samples from primary tumors and the paired liver metastatic tissue. The analyses included types and levels of mutations and copy number variation. APC and TP53 were the most commonly mutated genes in all samples with differing frequency between primary CRC (both 50%) and its metachronous metastasis (both 64%). While MPDZ gene mutations were restricted to primary tumors that developed metachronous metastases only, mutations in VCAN , MTCL1 , MDN1 , SHROOM2, SPEG , and GLI2 were more prevalent in primary tumors giving rise to synchronous metastases. FBN1 mutations were unique to synchronous liver metastatic tissue. Analysis of genetic interactions revealed different associations between mutated genes in patients with tumors of different chronicity, including driver genes such as TP53 , which was associated with APC in synchronous patients, while in primary tumors with metachronous metastases it co‐occurs with mutations in NBPF11 and PRAMEF15, respectively. The results suggest that distinct tumor progression pathways account for different chronicity outcomes further affecting patients' survival. However, larger studies are needed incorporating transcriptomic and epigenomic data to shed further light on the mechanistic chain from mutations to downstream gene expression regulation.

Hepatocellular carcinoma (HCC) is the third deadliest cancer worldwide. Its high mortality is primarily attributed to late-stage diagnosis. While mutations in driver genes, such as those encoding β-catenin (CTNNB1), tumor protein p53 (TP53), and telomerase reverse transcriptase promoter (TERTp) are well-documented in the literature, dysregulation of microRNAs (miRNAs), small non-coding RNAs that serve as crucial translational regulators, remains poorly understood. We conducted microRNA profiling by microarrays in 45 paired (tumor and non-tumor adjacent tissue) samples from non-viral HCC patients. We performed clinical correlation, ROC analysis and survival analysis of time to recurrence (TTR), disease-free survival (DFS) and overall survival. We identified 23 significantly dysregulated miRNAs (p ≤ 0.05, fold change ≥2). We investigated their differential expression and its relationship with clinical and pathological variables. Further, we found that miRNA-1972 may serve as an important positive prognostic marker because its high levels were associated with longer TTR and DFS. Significant positive results were obtained in receiver operating characteristic analysis for miR-1972, miR-3651 and miR-486-5p. miRNA-1972 is a strong prognostic marker in non-viral HCC. Dysregulation of several other miRNAs relates to pathological variables such as amount of stroma within tumor, microvascular invasion and micronodularity.