For tumor patients, disease diagnosis ultimately depends on bronchoscopy or pathological examination of the specimens obtained after surgical resection. Pathological diagnosis is the “gold standard” for tumor diagnosis. Any other examinations, such as CT, MRI, etc., even if a mass or lesion is found on the image, it cannot ultimately determine the nature and type of the lesion, and the diagnosis has to rely on pathological diagnosis. This is a very crucial basis in the process of tumor treatment. Today, we would like to popularize the knowledge related to lung cancer pathology report. 1.What information is included in a complete pathological diagnosis A complete pathological diagnosis includes four aspects of information: First, basic information of the patient, such as name, gender, age and pathology number. Among them, the pathology number is a unique number that each patient has in the hospital where the examination is performed and is very important. In addition, each hospital has the patient’s case number or ID number, etc., depending on the situation; second, the content of the report, i.e., the manner and location of the source of the specimen sent for examination. In other words, it is necessary to indicate the organ from which the specimen originated and by which way it was obtained, such as puncture, lumpectomy or surgical resection, etc.; third, the content of the pathology report. The content of the pathology report is the most important part of the entire pathological diagnosis, containing the type and nature of the lesion found through testing. The specimen obtained by surgical resection also contains the extent of tumor invasion, whether lymph nodes have metastasis and the presence of vascular aneurysm emboli. In addition, if the tumor lesion is atypical, the differential diagnosis should be added to the pathology report, and the differential diagnosis of tumor is often achieved by using immunohistochemistry. Fourth, molecular typing. For lung cancer, molecular typing is also a very important part of the pathological diagnosis report. However, the specific content of molecular typing report may be subsequently sent as a separate report, or it may be attached in the pathology report to form the fourth part. 2.The pathological diagnostic specimens are divided into large specimens and small specimens, and what they mean respectively Generally speaking, large specimens in pathological diagnosis refer to specimens obtained after surgical resection, while small specimens refer to biopsy specimens obtained by bronchoscopy, lumpectomy, gastroscopy or puncture. In addition, specimens obtained by biopsy on the surface of human body are also called small specimens. 3.What is the significance of adenocarcinoma, squamous carcinoma, large cell carcinoma, etc. in pathology report Lung cancer is divided into many subtypes, adenocarcinoma, squamous carcinoma, small cell carcinoma and large cell carcinoma are common types. And different types of lung cancer are treated differently. In addition, different types of lung cancer will affect the strategy and pathway of molecular detection. 4.What is the meaning of “immunohistochemistry” in pathology report? Immunohistochemistry, i.e. immunohistochemical test, is a common test in pathological diagnosis. In other words, the specimens sent for examination, whether small or large specimens, are sectioned and stained, and then the chromogenic agent labeled with antibodies is developed according to the chemical reaction, so as to determine the antigens in the tissue cells and to study their localization, characterization and quantification. Immunohistochemistry is useful for differential diagnosis of tumors in pathological diagnosis, determination of lung cancer types, and even for subsequent treatment of lung cancer. In addition, immunohistochemistry can be used to determine the molecular typing of lung cancer, i.e., genetic testing by immunohistochemistry. 5.What does “-” or “-” stand for? “-” means that the immunohistochemistry stain is positive, i.e. there is a gene mutation, and vice versa. “-” means the staining is negative and there is no gene mutation. Both “-” and “-” have clinical significance in differential diagnosis, and it does not mean that “-” is good and “-” is bad. -” is bad. EGFR and ALK are two common molecular types in lung cancer, and it is recommended worldwide that lung cancer patients must be tested for these two genes, because once a positive gene mutation is detected, patients will have targeted drugs with good efficacy to use. Therefore, if molecular pathology testing is necessary, both genes should be routinely tested. 7.In the report, what do EGFR-E746 (-) and EGFR-L858 (-) represent and what do they suggest in guiding treatment EGFR is a common mutated gene in lung cancer, and there are many fragments in this gene, and the abnormality of each fragment may have some significance in guiding clinical drug use. most of the gene fragments in EGFR belong to sensitive mutations, and some belong to non-sensitive mutations. EGFR-E746 and EGFR-L858 are the loci that are tested for some fragments in the EGFR gene test. When EGFR-E746 and EGFR-L858 show “”, it means there is a gene mutation, and if ” -“, it means that there is no gene mutation. In addition to these two test loci, other loci should be tested to see if the gene fragments corresponding to the test loci are mutated. When mutations are detected in certain fragments, patients must promptly consult their clinicians or pathologists for professional advice on the suitability of targeted drugs for the fragment with positive mutations. 8. Does ALK () mean that the patient needs targeted therapy The current expert consensus in China recommends immunohistochemistry (IHC), polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) for the detection of ALK gene. Whenever any of the recommended methods detects positive ALK, it indicates that the patient needs targeted therapy. One of the more commonly used immunohistochemistry methods is VentanaIHC, and if ALK is detected as positive by VentanaIHC, the patient can proceed directly to the subsequent targeted therapy without other molecular tests. 9.For patients who are already inoperable, how to make pathological diagnosis No matter pathologists or clinicians, as oncologists, for the diagnosis of tumor patients, without pathological diagnosis, any clinical diagnosis cannot be used as the final diagnosis. Therefore, when a lung cancer patient has reached an advanced stage and is no longer operable, he or she must find ways to get biopsy specimens as much as possible, such as obtaining specimens through bronchoscopy or puncture, or doing lymph node biopsy for superficial lymph node metastasis. Only when a pathological diagnosis is obtained can follow-up treatment be performed based on the diagnosis, otherwise all treatment is blind and unfounded. 10.Can such specimens also be tested for EGFR and ALK? Small specimens can be tested for EGFR and ALK genes. However, it is worth noting that large specimens do not pose any problem because of the sufficient amount of specimens, but small specimens require a standardized quality assessment before performing the test due to the limited amount of specimens. There are two main aspects to assess: first, whether the specimen taken has a tumor; second, whether the tumor content is suitable for genetic testing, as genetic testing requires sufficient cell volume for DNA extraction to be performed. Therefore, quality control of small specimens before testing is a very important part of quality control in the pathology department. After strict and standardized quality assessment, genetic testing is performed after small specimens are found to be free of any problems. Since the same testing method is used as that of large specimens, there is no big difference between the accuracy of the test results and that of large specimens.