What are biomarkers in the context of chemotherapy and immunotherapy?

Biomarkers, in the context of chemotherapy and immunotherapy, refer to biological molecules that are present in the body and can indicate how a patient is responding to treatment. These markers can be proteins, genes, or other substances that provide important information about the tumor's characteristics, the patient's health, and their likely response to specific therapies.

For instance, certain biomarkers can help determine whether a patient is likely to benefit from a particular immunotherapy by showing the presence or absence of specific immune checkpoint proteins. Understanding these biomarkers allows healthcare providers to personalize treatment plans based on the biological characteristics of the tumor and the individual patient's biology, potentially improving outcomes and minimizing unnecessary side effects.

The other options, while related to aspects of treatment, do not accurately define biomarkers. Physical side effects of treatment relate to the adverse effects experienced by the patient but do not provide information about biological response. Legal documents are unrelated to the biological indicators being discussed. Specific cancer types refer to the diagnosis of cancer but do not encompass the biological substances that indicate treatment response.