Blood serum is a component of blood important to the immune system. In this study, blood serum was collected from 10 men, both before and immediately after exercise. Each of these serum samples, two from each man, were then exposed to two types of cells:

LNCaP, which is a type of prostate cancer cell.

NIH3T3, which is an immune system cell.

The growth of the two types of cells was recorded after 48 hours.

Data Source: Rundqvist H, Augsten M, et al. 2013. Effect of Acute Exercise on Prostate Cancer Cell Growth. PLOS One 8(7):e67579.

• patient: A number assigned to each patient.
• cell: Type of cell, either "LNCaP" (prostate cancer cell) or "NIH3T3" (immune system cell).
• serum: When the serum was collected, either "before" or "after" exercise.
• growth: Cell proliferation, measured in arbitrary units. (Arbitrary units mean relative values are important but the absolute values are not.)