The observed mass shift was reproduced on replicate analyses, confined to CSNK1A1, and was not present in any normal colon samples, demonstrating that the one amu shift was not a simple artifact of sample procurement, processing, etc. Moreover, the observed one amu mass shift was consistent with a tumor-specific missense mutation (D→N), and a similar elution time shift had previously been observed in our labs upon mutation of a kinase active site aspartic acid to asparagine (in a different kinase). The gene discussed is CSNK1A1; the disease is neoplasm.