S-phase index (SPI), is a measure of cell growth and

viability Viability is the ability of a thing (a living organism, an artificial system, an idea, etc.) to maintain itself or recover its potentialities. Viability or viable may refer to: Biology, medicine or ecology * Viability selection, the selection of ...

, especially the capacity of tumor cells to proliferate.'' Oncology Nursing Forum'', Volume 18, p. xxv (Oncology Nursing Society, 1991). It is defined as the number of

BrdU Bromodeoxyuridine (5-bromo-2'-deoxyuridine, BrdU, BUdR, BrdUrd, broxuridine) is a synthetic nucleoside analogue with a chemical structure similar to thymidine. BrdU is commonly used to study cell proliferation in living tissues and has been st ...

-incorporating cells relative to the volume of DNA

staining Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in ...

determined from whole mount confocal analyses. Only cells in the

S phase S phase (Synthesis Phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cell division, the processes that occur during ...

will incorporate BrdU into their DNA structure, which assists in determining length of the

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA ( DNA replication) and some of its organelles, and sub ...

References

* Murphy, Terence D. "''Drosophila skpA, a component of SCF ubiquitin ligases, regulates centrosome duplication independently of cyclin E accumulation''", ''

Journal of Cell Science The ''Journal of Cell Science'' (formerly the ''Quarterly Journal of Microscopical Science'') is a peer-reviewed scientific journal in the field of cell biology. The journal is published by The Company of Biologists. The journal is partnered with ...

'' 116, 2321-2332 (2003). Cellular processes {{Cell-biology-stub