Yes. Lung cancer. Inoperable
Walter White after being told his diagnosis[src]

Lung cancer is a type of cancer caused by abnormal and harmful cell growth in tissues of the lung. The main types of lung cancer are small-cell lung carcinoma (SCLC), also called oat cell cancer, and non-small-cell lung carcinoma (NSCLC). The most common symptoms of lung cancer include coughing, coughing up blood, weight loss, and shortness of breath. Common treatments include surgery, chemotherapy, and radiotherapy. NSCLC is sometimes treated with surgery, whereas SCLC usually responds better to chemotherapy and radiotherapy.

In the premise of Breaking Bad, the protagonist, Walter White finds out that he is diagnosed with lung cancer, thus culminating the events of him deciding to cook methamphetamine in order to secure his family's future before he dies. The cancer also symbolizes Walt's decaying loss in his life, and contributing to his re-birth from Walter White to Heisenberg.

Jesse Pinkman's aunt Ginny also contracted Lung Cancer and she passed away a few years before the events of Breaking Bad. Due to his experiences with the treatments, Jesse recognizes Walter is undergoing chemo-therapy.

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