Light micrograph of a lung cancer biopsy (thin-section stained at h&e). We can see several blood vessels and a fibrous tissue infiltrated by atypical undifferentiated cells with different sizes of nuclei, some of them with eosinophil cytoplasm, adopting a pattern of infiltration of loose cells. Lung cancer is an uncontrolled cell growth in tissues of the lung. Causes: tobacco smoking (80?0% of cases), passive inhalation of cigarette smoke and exposure to radon gas, asbestos and other carcinogens. Treatment: surgery, chemotherapy and radiotherapy. It is the leading cause of cancer deaths worldwide. Field of view size: 370 x 550 痠 (0.015 x 0.022 in)