MEG3 and prostate cancer: It has been found that MEG3 is downregulated in many kinds of tumors, including oral squamous cell carcinoma [14], head and neck squamous cell carcinoma [15], lung cancer [16], esophageal squamous cell carcinoma [17], colorectal cancer [18], renal cell carcinoma [19], bladder cancer [20, 21], prostate cancer [22], cervical cancer [23, 24], leukemia [25], and meningioma [26].