ERBB2 and cancer: For example, if a user wishes to find publications on cancer-related genes, the query should contain specific terms such as “HER2,” “Carcinoma,” “Tumor,” and so on, rather than “cancer-related gene” because many publications on cancer-related genes do not contain the general term “cancer-related gene.” Furthermore, the topic words in a publication may provide only background information and may not be on the main topic of the publication.