This talk will describe some of the frequently used molecular techniques across different subspecialties of cellular pathology in relation to cancer diagnosis including immunohistochemistry, methylation profiling, fluorescence in situ hybridisation (FISH) and different sequencing modalities. It will discuss the advantages of using each of these techniques for the pathologist, and how they can help to further characterise a tumour ensuring a more accurate diagnosis. It will also discuss how these different tests are useful for identifying patients suitable for targeted therapies.