PIK3CA-mutations were significantly more often observed in steroid hormone receptor-positive than in steroid hormone receptor-negative tumours (OR 3.38, 95% CI 2.103-5.438), and in HER2-negative than in HER2-positive tumours (OR=2.25, 95% CI 1.451-3.501), respectively. Here, PIK3CA is linked to neoplasm.