Long noncoding RNA CLAN promotes lymphangiogenesis in the colorectal carcinoma

Metastasis is the main cause of colorectal cancer (CRC)-related death and lymph node plays a vital role in this process. Long noncoding RNAs (lncRNAs) are emerging as an important factor of biological progress in cancers. However, lncRNAs related to CRC metastasis was rarely reported. CLAN expression data of tumor tissues and normal tissues were obtained from GEPIA database and 23 paired tumor and normal samples of patients. CLAN expression of 85 patients was carried out with RNA extracted from FFPE samples and quantified with qRT-PCR. Patients’ clinical features were collected from department of Pathology of the Affiliated Hospital of Southwest Medical University. Immunohistochemistry staining was used to detect the metastasis-related proteins. CLAN was highly expressed in tumor tissues. And the expression level was not correlated with age, gender, differentiation, and location of CRC patients. Also, CLAN expression did not correlated with budding, LVI, and TILs. However, CLAN expression was strongly associated with lymph node metastasis and higher TNM stage. CLAN changed the lymphatic vessel density by promoting lymphangiogenesis but CLAN did not affect the blood vessel density. CLAN was a unique lncRNA that promoted lymphangiogenesis to accelerate CRC metastasis. CLAN might play a unique role in tumor early dissemination through lymphatic vessel.