Biostatistics and qPCR, Applications in Translational Research

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SELECTBIO

Guanylyl cyclase 2C (GUCY2C), an emergent intestinal tumor suppressor, is the receptor for the paracrine hormones guanylin and uroguanylin, gene products frequently lost early in colon carcinogenesis [1,2]. To date, we have completed two multi-center studies of GUCY2C expression, one in fresh-frozen lymph nodes and one in peripheral blood to assess the potential impact on prognosis in colorectal cancer patients. An additional study is ongoing that uses paraffin-embedded lymph nodes with a multiplex q-PCR assay. During this collaboration with the laboratory, we have developed statistical models to assess the selection of housekeeping genes [5], to measure expression levels [3], and to determine the association of expression with patient clinical outcomes [4]. Analysis using these approaches indicate that GUYC2C may be used to identify subpopulations of early stage patients who may benefit from chemotherapy. Longitudinal assessments and the pattern of trajectories may be used to indicate patients with potential to recur or die and could be used to inform clinical care. Current challenges include models to measure the multiplex assay, models that allow sufficient flexibility across q-PCR platforms, and the design of clinical trials that test implementation of biomarker-based therapy selection.