UCA1 and breast cancer: In fact, knockdown of lncRNA UCA1 by short interfering RNAs (siRNA) or short hairpin RNA (shRNA) has been shown to reverse drug resistance in various cancer cells such as bladder cancer [70, 71], breast cancer [38, 76, 77], lung cancer [87], gastric cancer [90, 91], colorectal cancer [34], prostate cancer [30], CML [62], ovarian cancer [24].