Recently, Christina Applegate learned her worst fears have come true – she has breast cancer.

While a rep for Christina, 36, says that she was diagnosed with an early form of breast cancer and the disease is not life-threatening, the Star magazine reports that the situation may be far more serious.

Christina’s mom, Nancy Priddy, underwent a double mastectomy in the late 70s and a hysterectomy 10 years later due to cancer. Now doctors have advised Christina that she has a genetic predisposition to the disease, an insider reveals. “Christina is taking this extremely seriously and is worried,” says her rep.

“No one wants to hear that they have cancer, especially at such a young age.” But Christina is not alone in this fight. Her ex-husband, Johnathon Schaech, has been by her side since she got the news. The couple split in 2005 but did not finalize their divorce until last year.

“Johnathon still loves Christina deeply,” says the source. “They are very close, and he has been a great source of strength for her. He’ll do whatever it takes to help her get through this.” [source: Star]