Disclosed are: a novel therapeutic agent for cancer such as esophageal squamous cell carcinoma a method for determining the prognosis of caner and a method for detecting cancer such as esophageal squamous cell carcinoma or determining the prognosis of the cancer using a sample that can be collected non invasively. The therapeutic agent for cancer comprises an antibody capable of performing an antigen antibody reaction with FGFRL1 to inhibit the proliferation of cancer cells or an antigen binding fragment thereof as an active ingredient. The method for determining the prognosis of cancer comprises determining the amount of expressed FGFRL1 in a cancer tissue separated from a living body wherein it is determined that the prognosis is bad when the amount of expressed FGFRL1 is large. The method for detecting cancer comprises measuring FGFRL1 or a fragment thereof extracted from a biological tissue or FGFRL1 or a fragment thereof in blood separated from a living body wherein it is determined that cancer is developed when the concentration of FGFRL1 or the fragment thereof is higher than that in a tissue or blood from a normal person.
