Which tumor biomarker is considered important for monitoring breast cancer?

The choice of PR (progesterone receptor) as an important tumor biomarker for monitoring breast cancer is grounded in its relevance to breast cancer pathology and treatment response. PR is a hormone receptor found in breast tissue that, when positive, indicates the tumor’s potential responsiveness to hormone therapy, such as tamoxifen or aromatase inhibitors. Monitoring PR status can provide insight into the biology of the cancer, help guide treatment decisions, and assess the effectiveness of hormonal therapies over time.

PR is particularly important in the context of breast cancer management to determine prognosis and tailor therapies based on receptor status. High levels of PR expression are generally associated with a better prognosis, while tumors that are negative may indicate a more aggressive disease and could require alternate therapeutic strategies.

Other biomarkers mentioned have less specificity or relevance to breast cancer monitoring. For example, CEA (carcinoembryonic antigen) is a marker that can be elevated in several cancers, including colorectal and lung cancers, and its role in breast cancer is limited. AF (alpha-fetoprotein) is more associated with liver cancer and germ cell tumors, while CA-125 is primarily used in the monitoring of ovarian cancer, not breast cancer. Thus, PR is the most appropriate choice for specifically monitoring