Which of the following is NOT typically detected by a liquid biopsy?

Liquid biopsy is a minimally invasive testing method that analyzes various components found in body fluids, primarily blood, to provide important information about cancer. It primarily focuses on detecting substances that indicate the presence of cancer, such as circulating tumor DNA (ctDNA), cancer-associated proteins, and circulating tumor cells (CTCs).

Cancer markers, found in the blood, can indicate the presence or progression of cancer. DNA mutations, particularly those found in ctDNA, are key targets in liquid biopsy for understanding the genetic landscape of tumors and their potential responses to targeted therapies. Circulating tumor cells, which are cancer cells shed into the bloodstream from a primary tumor or metastasis, are another crucial factor that liquid biopsies aim to detect to help assess disease status.

In contrast, protein levels in the liver are not the focus of liquid biopsies. While certain protein markers related to liver function or damage may be tested to monitor liver health, they do not provide direct information about cancer presence or progression in the same way that the other options do. Therefore, protein levels in the liver are not typically detected by liquid biopsy in the context of cancer evaluation.