The Department of Pathology at Peking University Cancer Hospital was established in 1976, making it one of the earliest and core departments in the hospital, as well as a National Key Clinical Specialty designated by the National Health Commission. "Diagnosis precedes treatment in oncology," and the Department of Pathology is responsible for determining the nature of lesions and tumors, clarifying tumor classifications, providing prognostic indicators, and performing molecular pathology testing and diagnosis, thereby providing evidence for clinical treatment. In recent years, the department's annual routine workload (including surgical resection specimens, biopsies, intraoperative frozen sections, and cytology) exceeds 80,000 cases, with over 30,000 consultation cases from other hospitals and more than 14,000 molecular tests per year. It holds diagnostic advantages in the pathological diagnosis of gastrointestinal tumors, lung cancer, breast cancer, lymphoma, melanoma, and other conditions. The department currently has 69 staff members, including 31 physicians, 30 technicians, 2 research personnel, and 6 medical assistants. Among the physicians, there are 10 chief physicians, 7 associate chief physicians, 12 attending physicians, over 10 residents and professional graduate students, and 27 with doctoral degrees. In the technical series, there is 1 associate chief technician, 9 supervising technicians, 11 technicians, and 9 junior technicians. Daily subspecialty expert-led discussions on difficult cases are held within the department, along with regular quality control case analyses. Relevant subspecialty personnel regularly participate in multiple multidisciplinary discussions at the hospital. Adhering to rigorous and standardized principles, the department ensures the accuracy and reliability of molecular pathology testing and diagnostic results. It participates in and passes multiple domestic and international inter-laboratory quality assessments annually. Experts from various subspecialties lead or contribute to the development of numerous domestic or industry consensus and guidelines on pathological diagnosis, tumor diagnosis and treatment, or pathological techniques, including the CSCO Lung Cancer Diagnosis and Treatment Guidelines, the Asia-Pacific Lung Cancer NCCN Guidelines, the Consensus on Pathological Diagnosis of Pulmonary Neuroendocrine Tumors and other lung cancer pathology-related consensus, the Consensus on Pathological Diagnosis of Colorectal Cancer, the Chinese Consensus on Pathological Diagnosis of Gastrointestinal and Pancreatic Neuroendocrine Tumors, the Consensus on Diagnosis and Treatment of Melanoma, the Consensus on Pathological Diagnosis of Breast Cancer, the CACA Guidelines for Pathological Diagnosis of Thyroid Cancer, the Consensus on Fluorescence In Situ Hybridization (FISH) Detection Techniques, and the Expert Consensus on EBER In Situ Hybridization Detection Techniques. The current department director, Professor Lin Dongmei, is a chief physician, medical doctor, and doctoral supervisor with nearly 40 years of experience in clinical tumor pathological diagnosis and research, specializing particularly in the pathological diagnosis and molecular pathology research of thoracic tumors. In recent years, she has led seven projects funded by the National Natural Science Foundation of China and Beijing municipal research projects, participated in major projects under the Ministry of Science and Technology, the National "973" key research projects, and the "863" major research projects, and published or co-authored over 100 SCI papers. Her research findings have been presented orally at multiple international lung cancer academic conferences, and she has led the publication of several lung cancer pathology-related consensus and guidelines. She also serves as a member of the Pathology Committee of the International Association for the Study of Lung Cancer, a member of the Expert Committee for the latest 6th Edition WHO Classification of Thoracic Tumors, a member of the Pathology Committee of the Chinese Medical Association, Vice Chair of the Tumor Pathology Expert Committee of the Chinese Society of Clinical Oncology, Standing Committee Member of the Tumor Pathology Professional Committee of the Chinese Anti-Cancer Association and Leader of the Lung Cancer Group, and Vice Chair of the Pathology Professional Committee of the Chinese Research Hospital Association. Since assuming the role of department director, she has led the department to achieve outstanding results in medical care, education, and research. The Department of Pathology currently has three doctoral supervisors and two master's supervisors. Research directions include tumor pathological morphology, tumor pathogenesis, clinical treatment-related pathological factors, and tumor biomarkers. The department has undertaken multiple National "973" projects, "863" projects, National Natural Science Foundation projects, Beijing major project initiatives, Beijing Overseas Returnees' Science and Technology Activities Merit-Based Funding, the Beijing Health Talent "Ten Hundred Thousand" Plan, and the "Beijing Health System High-Level Health Technical Personnel Training Program." In recent years, the department has published over 200 SCI papers as first or corresponding authors and over 50 papers in domestic core journals, receiving multiple Science and Technology Progress Awards from Beijing and the Ministry of Health, as well as honors such as the Beijing Health System High-Level Health Technical Personnel Discipline Backbone. Additionally, the department undertakes teaching responsibilities for graduate students, standardized training residents, visiting scholars, and rotating physicians, having trained nearly 30 master's and doctoral students and one postdoctoral fellow. It holds two pathology advanced training courses for visiting physicians annually (6 months and 12 months), training 6-12 pathology standardized training residents each year. In 2017, the department established a collaborative relationship with the Department of Pathology at Johns Hopkins University in the United States, engaging in comprehensive and in-depth cooperation in telemedicine consultations, teaching platforms, localization and promotion of software, and talent cultivation, learning and implementing world-class pathology teaching concepts, and striving to build a top-tier pathology department in a national cancer hospital.