(KTLA) -- Dave Coulier has been diagnosed with Stage 3 Non-Hodgkin lymphoma. The "Full House" actor told PEOPLE that in October he was diagnosed with an upper respiratory infection that caused lymph nodes to swell. While swelling in his armpits and neck was pretty normal when he was sick, he grew concerned when he noticed swelling in another area. He told the TODAY show he was shocked to find a "golf-ball size lump" in his groin area "within a week of falling ill." Apple Music selling $450 book of ‘100 Best Albums’ He went to the doctors, who performed bloodwork, an EKG, PET and CT scans and a biopsy. “Three days later, my doctors called me back and they said, ‘We wish we had better news for you, but you have non-Hodgkin's lymphoma and it's called B cell and it's very aggressive,’” he told PEOPLE.  Actor Dave Coulier poses on the press line at the "Comedy Central Roast of Bob Saget" in Burbank, Calif. on Aug. 3, 2008. (AP Photo/Dan Steinberg) "Non-Hodgkin lymphoma (NHL) is one of the most common cancers in the United States, accounting for about 4% of all cancers. (It) is a cancer that starts in cells called lymphocytes, which are part of the body’s immune system," according to the American Cancer Society. "B-cell lymphomas make up most (about 85%) of the non-Hodgkin lymphomas (NHL) in the United States. These types of lymphomas start in early forms of B lymphocytes (B cells)." Stage 3 means that the lymphoma has stayed within the lymph system. Coulier said going from " a little bit of a head cold" to being diagnosed with cancer "was pretty overwhelming." “This has been a really fast roller coaster ride of a journey," he said. Amid the seriousness of the diagnosis, the comedian hasn't lost his humor. “My joke is that in four short weeks, I’ve gone from a Virgo to a Cancer,” he told TODAY. “I’ve tried to retain a sense of reality but also a sense of humor about it.” Meanwhile, Coulier, his wife, Melissa Bring, and some of their "close friends in the medical field" have worked together to meet this "head-on." “We all kind of put our heads together and said, ‘Okay, where are we going?’ And they had a very specific plan for how they were going to treat this,” he said, noting that a bright spot in his diagnosis was when his bone marrow test came back negative. “At that point, my chances of curable went from something low to 90% range. And so that was a great day.”  Two weeks after his diagnosis he began chemotherapy and shaved his head. He then opened up about his health journey on his podcast "Full House Rewind" with Marla Sokoloff. “I started the podcast wearing a hat, and I said I've always been a man of many hats, but this hat has special significance because a couple of weeks ago, I was diagnosed with non-Hodgkin's lymphoma,” he explained on the episode. “That was really a conscious decision of, I'm going to meet this head-on, and I want people to know it's my life. I'm not going to try and hide anything. I would rather talk about it and open the discussion and inspire people.”  The discussion of cancer, sadly, isn't new to Coulier. “I lost my sister Sharon at 36 years old, breast cancer. I lost my niece Shannon at 29 years old, breast cancer,” he told the outlet. “I lost my mom, and now my sister Karen has cancer. So, over the years, I’ve seen what the women in my family have gone through, and it’s been not only an awakening but a learning process." Former Disney star Skai Jackson expecting her 1st child During this journey, Coulier wants to raise awareness and urge others to do something "as simple as pre-screening" like getting a "breast exam, mammogram, a colonoscopy or a prostate exam." “It’s a really simple thing to do, and it can add years to your life,” he said. In the meantime, he’s choosing to be positive as he’s expecting his first grandchild next year. His son Luc and his wife, Alex, are expecting a baby boy in March. “I’ve got to teach him how to play hockey,” he told PEOPLE. “There’s a lot to look forward to." For eight seasons, Coulier famously played Joey Gladstone on the hit ABC sitcom “Full House” alongside Bob Saget, John Stamos, Candace Cameron Bure, Jodie Sweetin, Mary-Kate and Ashley Olsen and Lori Loughlin. Coulier was a mainstay of the series from its beginning in 1987 until its cancellation in 1995. He reprised his role two decades later on the “Full House” spin-off “Fuller House,” which premiered in 2016. The show ran for five series ending in 2020.