Lung adenocarcinoma immunohistochemistry p40 is the use of immunohistochemistry in lung adenocarcinoma pathology to determine whether the tissue is squamous carcinoma of the lung, while a negative result rules out that it is squamous carcinoma of the lung. Lung adenocarcinoma immunohistochemistry p40 is the use of immunohistochemistry in lung cancer to identify the nature of lung cancer, such as adenocarcinoma, squamous carcinoma, etc., which is of guiding significance to the clinician in formulating the treatment plan. Negative test results indicate that squamous lung cancer can be ruled out, it does not mean that lung cancer is ruled out. It may be a benign tumor of the lung, or it may be adenocarcinoma or small cell lung cancer, etc. Lung adenocarcinoma immunohistochemistry p40 negative represents the low degree of malignancy of the tumor, the specific disease needs to be combined with the lung adenocarcinoma immunohistochemistry of other monitoring values comprehensive analysis, to formulate a scientific and reasonable treatment plan. It is suggested that patients should go to the hospital in time to improve the examination, and analyze the examination results and condition under the guidance of professional doctors to carry out targeted treatment.