The aim of this master's thesis is to provide an overview of current guidelines in certain areas of pathological diagnostics, specifically molecular pathological diagnostics of non-small cell lung cancer. Current guidelines for molecular profiling differ for various lung neoplasms. Pathohistological diagnosis is made per the latest classification by the World Health Organization from 2021, which divides lung neoplasms into epithelial, mesenchymal neoplasms, hematolymphoid tumours, and tumours of ectopic tissue. Guidelines and recommendations for diagnosing, treating, and monitoring patients with non-small cell lung cancer are provided by the NCCN (National Comprehensive Cancer Network) and ESMO (European Society for Medical Oncology). These guidelines are based on the results of the latest clinical studies, emphasising the importance of molecular testing for a personalised treatment approach. Emphasis is placed on key molecular alterations and their roles in cancer development, as well as the associated detection methods and therapeutic approaches. Due to their incidence and the existing drugs related to their presence, the dominant molecular changes are in the following genes: EGFR, ALK, ROS1 and KRAS. Detection of molecular changes is based on two laboratory methods: polymerase chain reaction (PCR) and next-generation sequencing (NGS). The PCR method allows rapid and precise amplification of specific parts of DNA or RNA to detect individual genetic mutations. NGS technology represents a significant advancement in sequencing DNA and RNA, enabling rapid and comprehensive analysis of a larger number of genes simultaneously, including the entire genome. Various NGS methods and their principles of operation are described, including Roche 454, SOLiD, Illumina, and Ion PGM, as well as third-generation technologies such as SMRT and nanopore sequencing, which are capable of sequencing individual DNA molecules in real time. Current guidelines highlight the importance of integrating molecular analyses into everyday clinical pathology diagnostics so that patients, with a current focus on patients with non-small cell lung cancer, have access to targeted treatment.