Tricky sepsis biomarker: Extremely high procalcitonin in squamous cell lung cancer with doubtful infection

Procalcitonin is a 116 amino acid polypeptide synthesized by the C-cells of the thyroid gland. Elevated serum procalcitonin levels are generally thought to be the result of systemic bacterial infection, but recent reviews have suggested an association between procalcitonin and patients with cancer. This case report discusses an illustrative case with elevated procalcitonin levels in a patient with squamous cell carcinoma and multiple metastases. The increase in procalcitonin in patients may be due to an inflammatory state in the tumour microenvironment. Elevated procalcitonin is associated with disease progression, the presence of metastases, and a poor prognosis.