She captured hearts across the nation as she realized her dream to play for Mount St. Joseph's women's basketball team in Ohio and raised $1.5million - all while battling inoperable brain cancer. And one of the millions Lauren Hill touched was LeBron James, who posted an emotional farewell letter to the teenager via Twitter on Friday, just hours after she passed away from her rare tumor. In the letter, the basketball star, dubbed King James, praised the 19-year-old for the 'leadership', 'courage' and 'strength' she had shown while suffering from Diffuse Intrinsic Pontine Glioma (DIPG). James, 30, who had never actually met Lauren, wrote: 'Dear Lauren Hill, You are the true definition of strength, courage, power, leadership, etc etc! Your time spent on earth will never be forgotten. Scroll down for video . Farewell: LeBron James (left) posted an emotional farewell letter to Lauren Hill via Twitter on Friday, just hours after the teenager passed away from terminal brain cancer. Right, Lauren plays college basketball last year . Praise: In the letter, James, 30, who had never actually met Lauren, wrote: 'Dear Lauren Hill, You are the true definition of strength, courage, power, leadership, etc etc! Your time spent on earth will never be forgotten' 'You inspired me': He continued: 'I [hate] that I never got the chance to meet u in person but know you inspired me the whole time! For every life u touched, u made the biggest impact [on] them by just being YOU!! 'I [hate] that I never got the chance to meet u in person but know you inspired me the whole time! For every life u touched, u made the biggest impact [on] them by just being YOU!! 'You're in a far better place now and please don't have too much fun up there w/o all your family and friends. Can u please tell my Grandma I said hello. 'Don't be afraid, she knows you cause we spoke about u plenty of times Until we officially meet again, take care and continue to be that LEADER we all love! ‪#‎RIPLaurenHill.' The Cleveland Cavaliers player signed off the letter - which was posted to his Twitter page - 'Sincerely, LeBron James'. The letter has since been retweeted tens of thousands of times. Many users have deemed the tribute 'touching' and 'beautiful'. One told James - who competed against the Milwaukee Bucks on Wednesday night - that it 'was so sweet it brought me to tears'. Lauren, who was diagnosed with a rare form of brain cancer shortly after her 18th birthday, had repeatedly defied doctors' expectations after they told her that she would not live past December. A touching tribute: James told Lauren not to have 'too much fun up there without all your family and friends' 'Tell my Grandma I said hello': He added that he had spoken 'plenty of times' about Lauren to his grandmother . #RIPLaurenHill: The Cleveland Cavaliers player signed off the letter - which was posted to his Twitter page - 'Sincerely, LeBron James' (pictured). The letter has since been retweeted tens of thousands of times . Instead, the Indiana native played four games with her team at Mount St. Joseph University in Cincinnati, and raised more than $1.5 million for research into the cancer she suffered from. But as her condition worsened, the teenager became an honorary coach and earlier this year, she moved to Cincinnati Children's Hospital. She passed away at the hospital on Friday morning. As news of her death became public, thousands of people across the country - both basketball fans and not - took to social media to express their sorrow at her death, and show support for her family. Only a year and a half ago, Lauren, whose cancer saw her rapidly gain weight, had been just another teenager preparing for college after deciding to play basketball for Mount St. Joseph. But a few weeks later, she started feeling dizzy while playing for her high school team in nearby Lawrenceburg, Indiana. Tests found her tumor and she was told she had less than two years left. Diagnosis: Lauren is pictured left in December 2013, and right, in December 2014, after her treatment for Diffuse Intrinsic Pontine Glioma (DIPG), a rare childhood brain cancer which changed her appearance . Brave: Lauren, who used her limited energy to inspire people and raise money for research into the cancer that ultimately took her life, is pictured in her room in Cincinnati last December - months before she passed away . In September, doctors gave her the devastating news she wouldn't make it past December - and after years as a standout player, Lauren's hopes of playing college basketball were put in jeopardy. However, the NCAA granted permission to move the school's opening game forward because of her worsening condition. On November 2, Lauren realized her dream of playing for the school. Incredibly, she scored the first and last baskets of the team's 66-55 victory over Hiram College. Diffuse intrinsic pontine glioma (DIPG) is a type of brain tumor found in the part of the brainstem at the lower back of the brain. Due to the tumor's location, it can cause double vision, difficulty controlling eye movement and facial expressions, and difficulty swallowing and chewing. It may also cause weakness in the limbs. The condition primarily affects children most often between the ages of four and nine. Between 100 and 150 new diagnoses are made a year in the U.S. Only 300 are made across North America and Europe a year. It can be treated with radiation, but chemotherapy is generally not effective and surgery is impossible due to the spread of the cancer into healthy tissue. Unlike with other childhood cancers, there has been little progress in improving treatments and cure rates for the condition over the last few decades. Fewer than 10 per cent of children with DIPG survive two years after their diagnosis. Source: DIPG Registry . 'It's a dream come true,' Lauren told reporters at the time. 'To play on a college court, to put my foot down on the floor and hear the roar of the crowd - I just love it so much. I love basketball. 'Everything that happened today was amazing. I'm truly happy, it's a really good day.' At the game, Lauren said she wanted to find a cure for the rare cancer, which has a less than 10 per cent survival rate and most often affects children aged four to nine. 'When I was diagnosed I remember kind of feeling lonely because nobody understood,' she said following the game, USA Today reported. 'And now that more people know about this story and the awareness of DIPG. 'I'm so happy that people know about it now and that we can get some research going and hopefully find that home run cure for cancer. And even though I'm probably not going to be around to see it, it's going to help a lot of people.' Lauren played in four games and made five layups before the spreading tumor made her stop. When the season ended, her team held its annual dinner in the hospital where Hill was being treated. She was also honored at local sporting events and was featured on a box of Wheaties - known as the Breakfast of Champions. The U.S. Basketball Writers Association voted her the Pat Summitt Most Courageous Award, which is normally awarded at the Final Four. Athletes from other colleges autographed No. 22 jerseys - her number - and sent them in support. As the cancer slowed her down, Lauren's family, friends and teammates took a bigger role in promoting her fundraising campaign - and she kept reminding everyone to appreciate life. 'Life is precious,' she told WKRC-TV before her death. 'Every moment you get with someone is a moment that's blessed, really blessed.' Final days: Lauren is pictured enjoying Easter (left) and St Patrick's Day (right) from hospital in Cincinnati . Fighter: The NCAA moved Mount St. Joseph's first basketball game forward last November (pictured) so that Lauren could achieve her dream of playing for collegiate basketball. She scored the first and last baskets . The co-founder of her nonprofit foundation confirmed Lauren's death in hospital on Friday. 'Through Lauren's fundraising and advocacy efforts, she not only became a spotlight on the lack of funding for cancer research, but she most certainly has become a beacon guiding researchers for years to come,' The Cure Starts Now co-founder Brooke Desserich said. Her nonprofit foundation helped to raise more than $1.5 million for cancer research. 'She's made an impact on the world, more so than me - more than I ever will do,' Lauren's coach Dan Benjamin said. 'I've gotten so many emails and phone calls from all over the world. People are contacting me because they want to share her story.' No information about a memorial has yet been released, but Lawrenceburg Schools superintendent Karl Galey said on Twitter that schools will be prepared to assist staff and students with counseling. Heroic: Lauren, pictured left, smiles at Pat Summitt after receiving the Pat Summitt Award during halftime of her first NCAA college basketball game in November last year. She went on to play four games for the school . Dear Lauren Hill, . You are the true definition of strength, courage, power, leadership, etc etc! Your time spent on earth will never be forgotten. I [hate] that I never got the chance to meet u in person but know you inspired me the whole time! For every life u touched, u made the biggest impact [on] them by just being YOU!! You're in a far better place now and please don't have too much fun up there w/o all your family and friends. Can u please tell my Grandma I said hello. Don't be afraid, she knows you cause we spoke about u plenty of times. Until we officially meet again, take care and continue to be that LEADER we all love! ‪#‎RIPLaurenHill. Sincerely, . LeBron James .
Lauren Hill was diagnosed with an inoperable form of brain cancer aged 18 .
Despite illness, she achieved dream to play college basketball in Cincinnati .
Also raised a huge $1.5million for Diffuse Intrinsic Pontine Glioma research .
She died in hospital on Friday, aged 19, after defying doctors' expectations .
Now, LeBron James has penned a touching farewell letter to the teenager .
In letter, he praises Lauren for the 'leadership' and 'strength' she showed .
Basketball star tells her: 'You time spent on earth will never be forgotten'