Abstract: The present invention provides a method of treating a disease associated with elevated KRAS activity or expression in a subject, comprising suppressing KRAS expression in the subject by targeting an expression regulatory region of KRAS gene using a CRISPR-Guide Nucleotide Directed Modulation (GNDM). Also, provided is a CRISPR-GNDM system for suppressing KRAS expression comprising (a) a protein selected from the group consisting of dCas9 or dCpf1, a fusion protein of dCas9 or dCpf1 and Kruppel associated box (KRAB), and (b) a guide nucleotide targeting an expression regulatory region of KRAS gene.