For example, oncogenic alterations such as mutations in KRAS (Kirsten rat sarcoma viral oncogene homolog), BRAF (B-Raf proto-oncogene, serine/threonine kinase), PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha) and EGFR (epidermal growth factor receptor) can be readily detected in the blood of patients with lung, colorectal, breast or pancreatic cancer, or melanoma. Here, PIK3CA is linked to familial pancreatic carcinoma.