PTK7 and neoplasm: High expression of PTK7 was significantly associated with lower grade (χ2 = 6.268, d.f. = 2, p = 0.044), higher NPI group (χ2 = 8.274, d.f. = 2, p = 0.016), ER-negative tumours (χ2 = 62.038, d.f. = 1, p < 0.001), PgR-negative tumours (χ2 = 144.180, d.f. = 1, p < 0.001), HER2-positive tumours (χ2 = 23.161, d.f. = 1, p < 0.001), and triple-negative tumours (χ2 = 26.109, d.f. = 1, p < 0.001).