11-year-old tickles his little sister — and discovers she has cancer

ESSEX, England — A brother is credited with helping to save his little sister's life during a tickle fight in early July.

The Huffington Post UK reported that 11-year-old Aaron East from Essex, England, was tickling his 7-year-old sister Amy East when he noticed a lump on her neck.

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Aaron's discovery led doctors to diagnose Amy with rhabdomyosarcoma, a rare cancer that affects fewer than 60 children in the UK, early.

“I was really guilty at first because I didn’t understand much of what I found," Aaron told The Huffington Post UK. "I didn’t know what to do at first but then I realized I needed to let a responsible adult know so I ran to (my mommy) and I’m happy I did."

Amy underwent surgery to remove part of the growth and is now undergoing chemotherapy.

According to the family's GoFundMe page, Amy is set to undergo proton beam therapy, a form of radiotherapy that is only available in the United States. They are raising money to cover the cost of the trip and short- and long-term financial costs.