What then causes the defect? There appear to be many causes ranging from possible protein excesses (e.g., Plk4), possible protein deficiencies (e.g., P53), radiation exposure, electromagnetic exposure, and excessive exposure to carcinogens. Of these, P53 deficiencies have attracted attention of researchers since P53 is believed to be a regulator of centrosome duplication and a tumor suppressor [2,13,46,59,66-69]. These many causes of centriole defects are beyond the scope of this paper. Nevertheless, a commonly occurring initial centriole defect is the growth of two or more daughter centrioles at the base of the mother centriole—as flower petals  (see Fig. 7).