Later, it was shown that up-regulation of miRNA expression in colon cancer tissue compared to healthy tissue was more frequent than its down-regulation [2], e.g., the up-regulation of miR-21, which targets the tumour suppressor genes programmed cell death protein 4 (PDCD4) and phosphatase and tensin homologue (PTEN) [7–9]. Here, PDCD4 is linked to malignant colon neoplasm.