PDCD4 and colorectal cancer: The most cited paper, “MicroRNA-21 (miR-21) post-transcriptionally downregulates tumor suppressor Pdcd4 and stimulates invasion, intravasation and metastasis in colorectal cancer,” [36] published in Oncogene in 2008, has accumulated 1669 citations, underscoring the foundational role of miR-21 in CRC pathogenesis.