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December 12, 1966


JAMA. 1966;198(11):1208-1209. doi:10.1001/jama.1966.03110240116041

The nonessential amino acid hydroxyproline is unique to collagen and appears in urine at the rate of 20 to 45 mg/day in peptide form, reflecting bone collagen turnover. Excretion is altered by rapid bone growth in normal children and by a number of benign disorders affecting bone collagen metabolism or renal tubular mechanisms. Of recent interest has been the finding of elevated hydroxyproline excretion in adult patients with tumors primary or metastatic in the skeleton.1,2

On the basis of X-ray films of the skeleton and evaluation of serum calcium and serum alkaline phosphatase, there appear to be three groups of cancer patients with elevated hydroxyproline excretion. Included in one group are patients with metastatic osteolytic bone lesions and fairly normal alkaline phosphatase level (without liver disease) who often are hypercalcemic, eg, patients with multiple myeloma. A second category takes in patients with osteoblastic bone lesions and elevated serum alkaline