Eddie Van Halen — the legendary guitarist and co-founder of Van Halen — has died after a long battle with cancer … TMZ has learned. Sources directly connected to the rock star tell us … he died at St. John’s Hospital in Santa Monica Tuesday. His wife, Janie, was by his side, along with his son, Wolfgang, his ex-wife Valerie Bertinelli, and Alex, Eddie’s brother and drummer. We’re told in the last 72 hours, Eddie’s ongoing health battle went massively downhill — doctors discovered his lung cancer had moved to his brain as well as other organs. As you know, Eddie has been battling cancer for well over a decade. Our sources say he’s been in and out of the hospital over the past year — including last November for intestinal issues — and recently underwent a round of chemo. Last year we reported … Eddie was flying between the US and Germany for 5 years to get radiation treatment. Though he was a heavy smoker for years, he believes he developed throat cancer from a metal guitar pick he used to frequently hold in his mouth more than 20 years ago