PTK7 and gastric neoplasm: Genes identified in breast cancer included ERBB3, LIV‐1 and SLC44A4; in colorectal cancer CD71, PTK7 and SLC44A4; in lung cancer SLC44A4; in prostate cancer LIV‐1 and PSMA; and finally in stomach cancer CD71 and CD74 (Figure 4E).