According to researchers at the University of California located in San Francisco, there is a noticeable increase in the amount of HIV and AIDS patients being diagnosed with lung cancer. There seems to be some correlation between having HIV/AIDS and developing lung cancer. That correlation appears to be smoking. In their studies, it was determined that HIV/AIDS patients who previously smoked were more susceptible to having undiagnosed respiratory and pulmonary infections which were untreated. This contributes to the likelihood of developing lung cancer. Of course, lung cancer is often diagnosed in HIV patients who have already been diagnosed with AIDS.