Disclosed is a method for monitoring early treatment response of a cancer treatment comprising measuring by magnetic resonance spectroscopy (MRS), for example, proton MRS, the amount of Choline present in the cancerous tissue before and after treatment； the treatment comprises administration of a cell surface receptor inhibitor, for example, an EGFR inhibitor, whereby a decrease in the amount of Choline after treatment is indicative of a positive response. The decrease in the amount of Choline represents the decrease in the internal cell membrane as a result of down regulation of the organelles and their secretory granules and their transport vesicles. Disclosed also is a method for determining effectiveness of a cell surface receptor inhibitor in the treatment of cancer. Further, the present invention provides for a method for monitoring protein translation in an animal having a cancerous tissue by MRS.
