"The PIK3CA mutation test is used to determine eligibility for a kinase inhibitor treatment in a subset of patients with breast cancer," Dr. Katherine Geiersbach says. That subset is postmenopausal women or men who have hormone receptor-positive breast cancer that has progressed despite endocrine-based therapy. The kinase inhibitor, known as alpelisid, targets the PIK3CA mutation. Learn more in this “Test in Focus.” https://bit.ly/3AkowUJ | Mayo Clinic Laboratories | Facebook