Michael Mullan was living his American dream, until a doctor's diagnosis brought his world crashing down.

The young Irishman and his long-term girlfriend Melissa relocated from Kildare to Boston - where he was told he had only six months to live.

The 26-year-old was first diagnosed with cancer as a 16-month-old. As he took up his scholarship at Harvard Law School in 2015, he was told that the cancer had returned for a third time.

However, he faced it bravely like he did when the disease threatened to derail his undergraduate studies at Trinity College Dublin.

Read more: Brave Irishman battling cancer for the third time raises funds for US treatment

While finishing his law and business studies at the Irish university, he underwent renal cancer surgery and had one-third of his kidney removed. He wowed everyone when he sat his finals and claimed a first-class honors degree mere months later.

Three years later, despite the earth-shattering diagnosis by Boston doctors, Mullan has earned his master's degree in law at Harvard while fighting the insidious condition.

While he still continues to battle stage four cancer, which had spread through his lungs and abdomen, his adoring girlfriend Melissa acts as his full-time carer.

"Mel is always there to show me the silver lining to every problem," he said.

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He recalled that while he attended lectures at the prestigious Ivy League school, Melissa would sometimes wait outside the lecture theater with a sick-bag and a wheelchair as he was often overcome by nausea during his worst days.

"I'd have to run out of some of the lectures to vomit. I found it hard to concentrate at times. But I had to keep up the studies in order to keep my student visa and health insurance," he said. 

"A master's degree in Harvard is difficult at the best of times. Chemo and the opioids pain medication affected my concentration," he added.

After graduating in May last year, the couple moved to Washington DC where Michael is enrolled as a PhD student in the law school at the American University

But he succeeded in graduating in May last year.

"I was lucky I was in the right city at the right time to get this treatment," Mullan said, acknowledging the innovative treatment he received at Boston's Dana-Farber Cancer Institute.

"The treatment, which kept me alive, would not have been available in Ireland.

"I would not be alive today if I had not got this specialized treatment. I was lucky too that I had health insurance because I was a student," he said.

"As long as I am a student I can retain my student visa to remain in the US and I can keep the health insurance to continue my cancer treatment."

The couple now live in Washington DC where Michael is enrolled as a PhD student in the law school at the American University. They still travel to the Dana-Farber Cancer Institute every two months for his ongoing treatment.

"The busier I am in college, the better I feel. It's good not to be solely concentrating on cancer all the time.

"I have my tumors but I'm on medication that keeps them at bay. I'm on oral chemotherapy every day and I'm on about 40 tablets every day as well. It's anti-nausea medication and pain medication. It's going to be a long-term battle," he said.

"In the past year, me and Mel have become a bit more spiritual. The greatest support for me is Mel herself. Without her, I wouldn't be able to get through every day.

To find out more about how you can contribute to Mullan's medical bills, see here.