A cytoskeletal or scaffold protein family named “septin” has been shown to be involved in diverse phenomena in the living body, including cell division. The term “septin” is derived from “septation,” which means division. The protein was discovered as a GTP-bound protein (a polymer) indispensable for the division of yeast cells. Several to dozens of septin subunits are linked together to form filaments tens of nanometers in length. Multiple such filaments combine to form structures assuming the shapes of ribbons, rings or spirals, measuring on the order of submicrons in size. In multicellular organisms, septin is known to be involved in cell division as well as in diverse cell functions after differentiation, although the exact nature of its actions remain to be determined. Septin 7 (hcdc 10), one of the most important subunits of the mammalian septin family, is known to be expressed in all cells. Abnormal levels or locations of septin expression have been reported in humans with cancer, degenerative neurological diseases (e.g., Alzheimer’s disease), male sterility, etc.