Biomarker for cancer diagnosis

Cancer biomarkers, typically proteins, nucleic acids, or other molecular entities, are indicators of the presence, risk, or progression of cancer in an individual. Their detection and quantification are crucial for early diagnosis and treatment, as they provide specific information about a person's biological condition [24]. One type is the diagnostic biomarker, which is a biological marker used to detect or confirm the presence of a disease or specific condition in an individual, thereby facilitating earlier and more accurate diagnosis. There are also predictive biomarkers that can forecast a person’s response to medical therapy or to a particular environmental exposure. In addition, these biomarkers can help determine which therapy is most effective for a specific patient. Furthermore, therapeutic biomarkers help assess the effectiveness of pharmacological interventions and evaluate treatment safety and outcomes. Through these biomarkers, researchers and clinicians can monitor whether a drug is achieving its intended effect or causing unwanted side effects. Finally, prognostic biomarkers are used to estimate the likelihood of clinical events, disease recurrence, or disease progression among patients with a diagnosis [25]. A variety of commonly used cancer biomarkers are listed in Table 1.

Biomarker | Cancer type | Source | Clinical use | Ref.
Alpha-fetoprotein (AFP) | Liver | Blood | Staging | [26]
Cancer antigen 125 (CA125) | Ovarian | Blood | Monitoring | [27]
Carbohydrate antigen 15-3 (CA15-3) | Breast | Blood | Monitoring | [28]
Cancer antigen 19-9 (CA19-9) | Pancreas | Blood | Monitoring | [29]
Carcinoembryonic antigen (CEA) | Colon | Blood | Monitoring | [30]
Epidermal growth factor receptor (EGFR) | Non-small cell lung cancer | Tumour | Treatment selection | [31]
HER2/neu | Breast, gastric, esophageal | Tumour | Monitoring, prognosis and treatment selection | [32]
Prostate-specific antigen (PSA) | Prostate | Blood | Screening and monitoring | [33]