BOSTON (CBS) – For Dan Katz, it all started as a college student.
"There was a booth in the student union center that was advertising the chance to save someone's life," said Katz, recalling when he decided to become a bone marrow donor. "And I had time in between a class so I registered, gave a sample."
Little did he know, that sample would go a long way.
The 29-year-old, who's now a Massachusetts State Police Trooper, would end up being a bone marrow match twice in the ensuing years.
"It's a rewarding experience, a good feeling to help someone's life like that, change their lives, save their lives," said Katz.
This summer he received a call that he was a match for a 59-year-old man with cancer. Five year ago, he matched a 13-year-old boy with leukemia who is said to be doing well.
"I'm just psyched to hear the procedure worked and I was actually able to save this kid's life," said Katz.
Katz knows this because he received an email from the boy's mom, which said in part "There are no words to describe the appreciation and thanks I have for what you did for my son...We like to call you our miracle from God."
And in a letter from the National Marrow Donor Program to Massachusetts State Police, Mindy Weismer wrote, "Please understand that what Mr. Katz is doing is very special and that he actually has the capability to save someone's life. He is not receiving any payment or reward for his selfless act."
"He did this on his own," said State Police Sgt. Byron Rizos. "He took the initiative to do this because that's the type of person that he is. It's a great public service."
Katz says he is "confident that any of my co-workers would have done the same thing if they had the chance because we all have the same mindset of helping others."
Despite the pain and fatigue of the donation procedures, Katz says he'll do it again if he's a match a third time.
"I can't say no to the opportunity to save someone's life, it's a no-brainer."
To learn more about the bone marrow registry, visit the Be the Match website.
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