was kostet ein gentest für krebs — which blood markers matter?

The question about the cost of a genetic test for cancer and which blood markers matter cannot be answered from the provided context. The context covers CYP1A2 caffeine metabolism, general supplement advice, and a TCF7L2 diabetes SNP. For cancer genetic tests, prices vary: direct-to-consumer tests (e.g., for BRCA1/2) often cost several hundred euros, while clinical tests may be covered by insurance if familial risk is present. Blood markers such as tumor markers (PSA, CA-125, CEA) are established but not part of typical home genetic tests. Evidence for their utility ranges from moderate to strong depending on cancer type. Without relevant context, the answer must be conservative: consumers should seek medical guidance and not rely solely on home tests. Evidence is rated as 'unclear'.