Model validation and uniform resource locator. (A-D) Kaplan-Meier survival analyses (time in months) for the external validation of the model using external data from the MD Anderson Cancer Center (MDACC) vs the original data for each cluster: GC-1 (A), GC-2 (B), GC-3 (C), and GC-4 (D). (E) Screenshot of the Web site interface to our model.