circ_0005615 is up-regulated in CRC tissues and cells. (a) circ_0005615 expression in normal tissues (n = 30), the less-radiosensitive group (n = 14), and the high-radiosensitive group (n = 16) was examined by qRT-PCR. (b) The level of circ_0005615 was measured in NCM460, LOVO, and SW480 cells (n = 3). (c and d) Levels of circ_0005615, GAPDH, and U6 were detected in nuclear and cytoplasmic fractions (n = 3). Data are shown as mean ± SD. *P < 0.05.