The present invention provides methods and kits for the prognosis of survival time of a patient suffering from a cancerous tumor. The method involves quantitating the density of Th17 cells at the center of the tumor and at the invasive margin of the tumor, where low density values at each location indicate a favourable prognosis, high values at each location indicate an unfavourable prognosis, and heterogeneous values at the two locations (one high, one low) indicate an intermediate prognosis.