Zach Sobiech, 18, a Minnesota teen whose farewell song became a YouTube sensation, has died after a 31/2-year fight with bone cancer.

Mr. Sobiech died Monday at his Lakeland home. His mother, Laura, said on the CaringBridge website that he was surrounded by his family and girlfriend.

He was diagnosed with osteosarcoma in November 2009. When he learned last year that he did not have much longer to live, his mother suggested he write farewell notes to his loved ones. Instead, he wrote music.

His farewell song, "Clouds," has received more than four million views on YouTube - at http://bit.ly/UIGq9r - in just two weeks. The song is also on iTunes, reaching No. 1 on Wednesday, with proceeds going to the Zach Sobiech Osteosarcoma Fund.

Other musicians have covered the tune, and it inspired a celebrity video on YouTube.

Mr. Sobiech went through surgeries and chemotherapy, and spent some time cancer-free. But last May, cancer was found in his pelvis and lungs - and he was told he had months, maybe a year, to live.

"I want to be remembered as a kid who went down fighting, and didn't really lose," he said.

- AP