"Being a father has shaped my response to this," Siporin said during the second week of his cycle, as his kids chased an ice-cream truck in the twilight. He had to decide whether to live or die when he was told, back in January 2008, that his cancer would, sooner or later, kill him.
"I thought about suicide," said Siporin, an atheist. "I thought, I may have to get a gun. But there's no way I could do that to my family. I made a decision right there to spend as much time as I can with my wife and children."
The reason • Each morning during that first week, Matan and Siena wake up hours before school and day care to descend into their father's private hell.
Matan gently wakes up his father with a kiss to his forehead first, and then a kiss on the nose.
Siena curls up on the couch next to her father, and with her older brother propped up on an ottoman, they turn on the TV and watch the Disney Channel's "Phineas and Ferb" together.
Sometimes, Siporin will awake for a blurry moment and catch his kids playing a sad variation of doctor. They play "cancer." But seeing his children as he opens his eyes is Siporin's highlight of those days.
Matan's kisses in the morning are "the reason why I go through this," Siporin says. "Those moments give me so much of the strength to keep going."
Near the end of the first week, he feels better and forces himself to eat and drink.
The chemiluminescence of illness • Siporin is constantly looking for moments to remember why he continues palliative care that saps his will and resolve.
He doesn't have to look far. He has his family, as well as his remarkable way of getting through a near-unbearable situation: humor.
Siporin chooses to spread his positive attitude with fellow patients, whether it's dressing as a leprechaun or leading a flash mob in the cancer ward, or even performing a stand-up routine at Wiseguys Trolley Square where he wears his own T-shirt imprinted with the slogan "F- Cancer."
He works part-time at ARUP Laboratories at Research Park, where his wife also works.
"Most of the patients adore him," said Jon Weis, Siporin's Huntsman Cancer Institute physician and a clinical assistant professor at the University of Utah School of Medicine. "He has maintained his sense of humor. That's innate to him. It's all him."
It's an incredible feat when you realize that Siporin was given a death sentence four years ago.
When he visits the hospital, Siporin keeps himself sane by pulling good-natured pranks on fellow patients and medical staff.
Back in 2008, when he was first diagnosed with a malignant tumor and had to undergo a battery of tests, he furtively broke open a glowstick and rubbed the inside chemiluminescence all over his backside. The radiation doctors were shocked when they turned off the lights as Siporin asked them if anything was wrong.
He once hid a salami under his robe in an attempt to embarrass an unsuspecting MRI technician leading his wife to ask him if he's 12.
One Halloween, with the approval of the nursing staff, he had a friend dress up at the Grim Reaper and go through the ward, asking patients if they were Siporin. Out of nowhere, Siporin jumped out and began "beating" the Grim Reaper.
'Every day is a win' • But Siporin most cherishes time with Matan and Siena, whether he's taking them to Jazz games, strolling through The Gateway or enrolling them at his taekwondo dojo.
A movie buff, Siporin always goes to midnight screenings so he has time to tuck his children into bed earlier. He sings them lullabies until they fall sleep.
Movies represent goals, and measuring points, in a life where tomorrow isn't guaranteed or, in some cases, promises to be excruciating.
He went to "The Avengers" even though it was chemo week. Siporin can't wait until "The Dark Night Rises" opens in July, closing out Christopher Nolan's Batman trilogy. Siporin jokingly curses director Peter Jackson for chopping the upcoming film "The Hobbit" into two parts, so that the second installment won't hit theaters until December 2013, rather than this December.
Anniversaries and reunions are another measuring stick. In October, Steele and Siporin celebrated their 11-year anniversary, and the two high-school sweethearts hope to attend their 20th Logan High School reunion this summer.
She continues to tell him, "Every day is a win."
The mystery of what's next • Steele is an amiable, quiet woman who shares the same brown hair color as her husband before he lost the rest of it to cancer, while their children share the blond hair color both parents sported when they were young.
"There isn't a lot I can do for him," she said. "It's hard to watch that kind of suffering and pain every other week."
The couple talk to their kids about the afterlife and tell them that it's a mystery, and that everyone will find out whether it exists when or if they arrive.
"We live in a weird way," Siporin said, "where we plan on growing old, and also plan for the worst. It's planning for the future, and planning for no future."
The children know their father is sick, though it's hard to tell how much they comprehend. They probably know more than their parents would like them to, Siporin says, which explains their regular nightmares.
He tries to temper their anxieties with love and fun during the two weeks each month that he feels well.
Three years ago, Siporin and his family flew to Florida and visited Walt Disney World. At the end of the day, Steele told Siporin that when Siena turned 5, the family should come back. Siporin didn't want to make promises he couldn't keep. He told his wife: "I'll be dead by then."
Last month, as Siena turned 5, the family spent a week at Disney World.
"I thought I would never reach it," Siporin says. "I got to see my daughter's five-year birthday, and I got to see my son's eighth birthday, which is the greatest thing in the world."