More women who are not smokers are being diagnosed with lung cancer, but why?

HOUSTON, Texas (KTRK) -- Lung cancer is the number one killer for both men and women, but more women who have never been smokers are diagnosed with it, according to a doctor at MD Anderson.

Dr. Mara Antonoff said for too long, we have unfairly labeled lung cancer as a smoker's disease. The truth is anyone of any age can get lung cancer from their environment alone.

But this lethal disease is essentially going unnoticed because it's underfunded and understudied.

Mandi Pike is currently undergoing treatment at MD Anderson. The mom has never smoked a day in her life but was diagnosed with lung cancer.

Lung cancer, the third most common in U.S., often goes unnoticed. Here's why, according to a doctor.

It started with a persistent cough and eventually bronchitis. Doctors finally found the mass when she got a CT scan. It has been extremely hard on her, but she is trying to stay positive.

About three weeks ago, I was diagnosed with LMD disease, so my lung cancer has spread in and around my brain. So my treatment is different. This is pretty new," she said. "This would be easier if I did not have the stress of how am I going to raise the kids. I want to be here with my kids. That's always in the back of my mind, that I'm not going to be here. It's just really hard."

However, she said the doctors at MD Anderson are giving her hope and it is making all the difference.

Here are some signs you need to look out for, according to Antonoff:

• A persistent cough that does not go away with antibiotics
• If you develop a wheeze
• Coughing up blood

• Chest pains
• Weight loss
• Change in voice

If you develop any of those symptoms, you need to get evaluated right away and see about getting a CT scan.