The present disclosure relates to the field of medical devices generally and specifically, to endoscopic systems and methods for resection of malignant and pre-malignant lesions within the gastrointestinal (GI) tract. In particular, the present disclosure relates to systems and methods for delivering injectable compositions between tissue layers (e.g., between the muscularis and submucosa layers) to elevate and stabilize the lesion for fast and efficient resection.