Question

Substances such as enzymes, antigens, and hormones present in the circulation that can be used for cancer screening, to confirm a diagnosis, or to monitor the clinical course of a malignancy are called:

Answer 1

Analytes.

Step-by-step explanation:

An analyte is a substance/bio-molecule which is being analyzed with the help of a laboratory procedure or test.

In case of cancer, the cancerous cells produce different analytes (enzymes or antigens or hormones) than the normal cells do. So if we detect a different analyte than the normal analyte then we can easily infer that the person being analyzed has cancer.