RIVERSIDE (CBSLA.com) — Two Riverside firefighters are leaving Thursday to climb the highest peak in Europe as part of a fundraiser for kids with cancer.

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Dave Lesh said the 11-day expedition to Russia’s Mount Elbrus is in honor of Jacob, 4, who is batting brain cancer. Though not blood-related, Lesh considers the young Beaumont boy his grandson.

“I’m going to take a picture of him with me and leave it on the summit in honor of him,” he said.

Lesh and fellow firefighter, Matt Mathis, will join eight others and climb Mt. Elbrus, which peaks at 18,510 feet.

“It’s 4,000 feet higher than I’ve gone so far,” said Mathis.

Mathis has been a serious climber for about six years. Lesh has been mountain climbing for 26 years.

“Dave has climbed some major summits before and has been a mentor for me the last couple of years,” said Mathis.

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Mathis climbed Mt. Whitney with his girlfriend. He’s also reached the summit on Mt. Rainier and Mt. Shasta.

“But all those top out at 14,500. This is going to be 4,000 feet higher. This will definitely be a big step to see how the body acclimates. How I do at the higher elevations,” said Mathis.

Lesh, who’s a division chief with Riverside fire, has climbed the tallest peaks in North and South America and Africa.

He said reaching the top of Mt. Elbrus would mean he’s climbed the tallest mountain on four continents.

“When you’re standing there on the summit looking out, and you’re on the tallest peak for as far as you can see, it’s a feeling you can’t describe,” said Lesh.

Lesh and Mathis, who are paying all costs for the trip, hope to reach the summit of Mt. Elbrus on Sept. 3.

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Plus, they helped raise $22,000 for St. Baldrick’s Foundation, a non-profit that funds children’s cancer research.