Normalization of Elevated Tumor Marker CA27-29 After Bilateral Lung Transplantation in a Patient With Breast Cancer and Idiopathic Pulmonary Fibrosis.

Solid tumors involving glandular organs express mucin glycoprotein that is eventually shed into the circulation. As a result, these proteins can easily be measured in the serum and be used as potential tumor markers. The most commonly used tumor markers for breast cancer are CA27-29 and CA15-3, which both measure the glycoprotein product of the mucin-1 (MUC1) gene.