CA9 and breast cancer: In addition, CA-IX plays an important role in cell migration [14], and its expression has been reported to be a prognostic marker for several types of cancer, including non-small cell lung cancer [15], breast cancer [16], head and neck tumors [17], bladder cancer [18], brain cancer [19], cervical cancer [20], esophageal and gastric cancer [21], rectal cancer [22], soft tissue sarcoma [23], and gallbladder cancer [24].