Cancer is found in the lining of the chest wall and the lymph nodes on the same side of the chest. Cancer may also be found in the lining of the lung, the lining of the diaphragm (the thin muscle below the lungs and heart that separates the chest from the abdomen), or the lining of the sac that covers the heart on the same side of the chest. Stage II malignant mesothelioma is advanced malignant mesothelioma.