Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Lung adenocarcinoma ?
    ### Response:
    Lung adenocarcinoma is a cancer that occurs due to abnormal and uncontrolled cell growth in the lungs. It is a subtype of non-small cell lung cancer that is often diagnosed in an outer area of the lung. Early lung cancers may not be associated with any signs and symptoms.
    