Stanniocalcin-1 as a novel marker to detect minimal residual disease of human leukemia.

Stanniocalcin is a glycoprotein hormone that regulates the calcium level in fish. We found that mRNA of human stanniocalcin 1 (STC-1) is detectable in phytohemagglutinin-stimulated T cells and in most human leukemia cell lines, suggesting a role of STC-1 for cell proliferation. This finding prompts us to study the usefulness of STC-1 for monitoring acute leukemia. The levels of STC-1 transcripts increased in patients with acute leukemia at diagnosis and relapse, as judged by quantitative real-time RT-PCR. Levels of transcripts rapidly decreased to within the cut-off levels, when the blast numbers decreased with chemotherapy. Prolonged elevation of STC-1 levels after treatment was associated with a poor prognosis. All of 7 patients relapsed 1 to 4 months after they showed an elevated level of the transcripts in clinical remission. These results indicate that STC-1 is a novel marker for minimal residual disease of acute leukemia, and for an early diagnosis of relapse.