biochemistry in malignancy | Notion

Serum tumour markers

Serum tumour marker	Neoplasms
Alpha fetoprotein (AFP)	Hepatocellular carcinoma, GI cancers, metastatic lung cancer, germ cell tumours
β-human chorionic gonadotrophin (β-hCG)	Choriocarcinomas, germ cell tumours, lung cancers
Prostate-specific antigen (PSA)	Carcinomas of the prostate
Carcinoembryonic antigen (CEA)	GI cancers
CA125	Ovarian cancer
CA19-9	GI cancers, particularly pancreatic cancer
CA15-3	Breast cancer
Osteopontin	Many cancers, including mesotheloima
Calcitonin	Medullary carcinoma of the thyroid
Thyroglobulin	Papillary and follicular thyroid cancer

Hypercalcaemia

If a patient has high calcium levels, the most important investigation is PTH
If calcium is high and PTH is low, the parathyroid glands aren’t responsible for the elevated calcium (calcium/PTH feedback loop is normal) and therefore the high calcium is due to PTHrP - only ever present in malignancy

Alkaline phosphates (ALK)

Used as an ‘entry level’ monitoring test for metastatic disease to liver or bone
Follow up tests - GGT (elevated in liver pathology) and a bone scan (to investigate bone pathology)

Obstructive liver picture

Malignancy can obstruct the biliary tree, causing a cholestatic LFT pattern
- ALP > ALT/AST, with high bilirubin
SAAG can be used in investigating the cause of ascites

Pleural effusion

An exudative pleural effusion (fluid protein ≥ 30 g/L) is more likely to be caused by a malignancy