In June 2013, Friske began to complain of headaches - two months after the birth of her son Platon - and was diagnosed with glioblastoma shortly afterwards. She underwent treatment in the USA and Germany. In January 2014, her diagnosis was confirmed in a statement on Friske's official website. In January 2014, she started treatment at the New York Memorial Sloan Kettering Cancer Center. In the summer of 2014, Friske underwent rehabilitation in Jurmala, Latvia, where she celebrated her 40th birthday. She continued her course of treatment in China and then returned to Moscow in October, refused a wheelchair and began to move independently. In February 2015, Friske had resumed treatment in the Los Angeles clinic. Later, she continued her treatment at the N. N. Blokhin Russian Cancer Research Center in Moscow. During the treatment, her condition gradually worsened and she fell into coma. On June 15, 2015, Friske died due to complications of glioblastoma at her house in Balashikha, near Moscow, at 22:07 at the age of 40, spending the last three months of her life in a coma. The farewell took place on June 17 at the concert hall Crocus City Hall. The funeral service took place on June 18 at the Epiphany Cathedral in Yelokhovo. She was buried at the Nikolo-Arkhangelsk cemetery.