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By Chris Serico

A Facebook plea for users to share photos of their dogs to cheer up a cancer-stricken Arizona teen has yielded more than 500,000 pictures, according to one of its organizers.

Roberta Lucero-Koron launched the "Photo Doggies for Anthony" campaign in December to raise the spirits of Anthony, the son of her Phoenix friend, Kristen Lyons. Lucero-Koron and Lyons' Facebook page says Anthony has been and out of the hospital, undergoing chemotherapy treatments for acute lymphoblastic leukemia.

"Hi all, my friend Kristen Lyons has her son Anthony at Phoenix Childrens hospital," Lucero-Koron wrote. "Some days he gets doggy visits and some he does not. They make him smile. I thought if I create this event, you can post a picture of your dog to help make him smile. His mom shows them to him and he smiles."

"Friday" from Westfield,MA. Just turned 3 years old on New Years Eve, and has finally stopped eating the furniture. get better Anthony.Tammie Carrier-Wilda‎ / Today

Word spread far beyond friends and family as the Facebook page went viral. As the puppy pics started pouring in, the updates followed. Anthony spent his 16th birthday at home Dec. 26, according to a post labeled as authored by Lyons.

"I also want to thank each and every one of you for sending your doggie and occasional kitty pictures," Lyons wrote. "We have laughed, ohhhed and ahhed at every single photo and video so far it has really been a joy and I appreciate everyone sharing their pets with us and the personal messages to Anthony are truly awesome."

Hey Anthony Lyons! My name is Checkers and I'm from Simpsonville, South Carolina! My Mama rescued me 3 years ago and I Love my family! Hope you feel better soon!!Mary Anne Johnson Spivey‎ / Today

The dog photos kept coming. According to a Dec. 31 update, Facebook users from the United Arab Emirates to Australia sent more than 2,000 photos, and there was no end in sight. "I cannot express the joy we have gotten from these photos," the update reads. "We have looked at each and every photo and video and we laugh and sometimes cry just from the outpouring of support."

Good morning Anthony! He's not my dog, and it's not my picture, but this is one of my favorites. Feel better!Brenda Donovan Jackson / Today

With Anthony reportedly facing another week of chemotherapy in the hospital starting Jan. 2, Lucero-Koron made another Facebook appeal: "He needs your photos and prayers. GOD BLESS YOU ALL."

Supporters responded in exponential and adorable fashion. As of Sunday, more than a half-million dog photos from all over the world were shared with the family, according to the Facebook page.

Hi, my name is Bucky, I am a 10 year old Cairn Terrier and I live in Brighton, Michigan. My Mom and Dad gave me the name Bucky because my front teeth are so "bucked" that my tongue hangs out. I hope this puts a big smile on your face. Feel better soon.Lisa Wagner Miller‎ / Today

And as of Monday afternoon, more than 810,000 Facebook users had added themselves as "guests" of the ongoing Facebook event.

"God Bless you and God Bless the World Wide Web," Lucero-Koron wrote Jan. 4. "Anthony is smiling joyfully because of YOU. ... One thing I have to say is, make yourself smile too by looking at these beautiful animals that God gave us. I can't stop crying from tears of happiness."

Follow writer Chris Serico on Twitter.