Unique role of the prospective cohort incident-tumor biobank method in etiological research

Conventional tumor tissue biorepositories are collections of tumor specimens and associated metadata from cancer patients for ongoing or future clinical studies with or without tumor-free control individuals. Herein, the term “case-series-based design” (encompassing the case–control design) is used for this type of tumor biorepositories. In contrast, investigators have collected tumor tissue specimens from incident cancer cases that occurred in large-scale prospective cohort studies, which followed cancer-free participants (typically, each study with >50,000 participants) for years/decades to assess long-term exposure statuses and cancer incidence.