Genomic imprinting is an epigenetic regulatory mechanism in mammalian embryo development and tumorigenesis. In normal somatic cells, paternal and maternal alleles of an imprinted gene are differentially methylated in an allele-specific manner, resulting in the silencing of one allele and activation of the other. In cancers, the normally silenced allele is often aberrantly activated in certain imprinted genes, resulting in the expression of both alleles. This phenomenon is termed loss of imprinting (LOI) which is associated with various cancers. We adopted a nascent RNA in situ hybridization method, targeting the short-lived introns to label and visualize the transcription sites and characterize the transcriptional regulations of imprinted genes. We developed an objective quantification of these imprinting alterations by measuring the biallelic (BAE), multiallelic (MAE) and total (TE) expressions of various imprinted gene panels which we termed the Quantitative Chromogenic Imprinted Gene In-Situ Hybridization (QCIGISH) method. We have applied QCIGISH to investigate the diagnostic, prognostic and therapeutic significance of the allelic expression status of imprinted genes with the hope of driving better clinical decisions and improving health outcomes. With this technology, we are dedicated to the accurate and early identification of cancers at their most curable stages, providing a personalized pathway towards necessary and effective therapies while avoiding inessential, costly and potentially futile treatments, prolonging the survival and improving the quality of life of cancer patients everywhere.