MSH6 and neoplasm: They are represented by the whole blood MSH6 level, reflecting the mass transfer from tumor to blood; the blood-to-urine ratio (r1), reflecting elimination via the kidneys; the blood-to-saliva ratio (r2), reflecting elimination via the salivary glands; and the sum S = 2 × [MSH6]urine + [MSH6]saliva, reflecting the total elimination in the hypothesis of a urinary output twice the salivary output and, for some locations, the MSH6 level in urine.