Figure 1

Journal-Journal Inter-Citation Network of the Cancer Literature in 2009. Each node represents a specific journal. The size of the node indicates the prominence of the journal in the literature (specifically, number of articles published in 2009). The map shows the 75 journal in our dataset (the citing journals, shown with circular nodes, e.g. the Journal of Clinical Oncology) and the 200 most cited journals (shown with square nodes if they are not in the citing journal set, e.g., the New England Journal of Medicine). Each line reflects an inter-citation relationship between the two journals. To increase legibility, only the 15% most specific links are included. Tightly connected journals appear close to each other. Tightly linked sub-networks can be seen by the dense web of connections among them. The nodes and journal names are color-coded according to research levels: blue for clinical observation, green for clinical mix, orange for clinical research, and red for basic research. Journals dedicated to basic science and molecular biology cluster at the top, with Cancer Research and Oncogene forming the largest nodes. Journals focused on clinical topics, such as the Journal of Clinical Oncology and Cancer cluster at the bottom. Between the two poles can be found a translational interface of clinical research and clinical mix journals. Journals focused on solid tumors are to the left (e.g., Breast Cancer Research, Prostate, Gastroenterology), and journals focused on hematologic tumors are on the right (e.g., Blood, Leukemia).