If someone you love is diagnosed with breast cancer, your support will be an important part of her treatment.

According to the National Institutes of Health (NIH), most people with cancer want to share the diagnosis with those closest to them. As a best friend, you will probably be one of the first to know. Initially, it will be an unsettling, emotional time for you both. You will have to deal with your own feelings of vulnerability and mortality, as well as the stresses of helping a friend cope.

As a best friend you will be there for her during times of hope and despair, courage and fear, humor and anger, and the unknown. You may be the outlet for feelings she may not be able to express to anyone else. For example, anger is a very common feeling. Many emotions, like fear or worry, come out in anger. Just remember to not take it personally, she is counting on you.

Best friends know each other's coping rituals, whether it is a good cry, talking, a mouthful of expletives, or temporary withdrawal. My own best friend immediately responded to her diagnosis of breast cancer in her usual manner—a take charge attitude with a dash of humor. As Betty Rollins, a breast cancer survivor and author of First You Cry, wrote: "Cancer won't bestow a sense of humor on someone who doesn't have it, but a sense of humor can sure get you through the experience.''