Abstract: The present disclosure is directed to progastrin monoclonal antibodies, fragments thereof, compositions comprising progastrin monoclonal antibodies, and methods of making and using progastrin monoclonal antibodies and compositions thereof. The present disclosure is directed to methods of treating colorectal cancer with progastrin monoclonal antibodies and compositions comprising progastrin monoclonal antibodies or fragments thereof. The present disclosure is further directed to methods comprising detection of progastrin, including methods of diagnosing colorectal cancer and methods of monitoring efficacy of anti-cancer therapy in subjects suffering from colorectal cancer.