PLK1 and neurodegenerative disease: Taking note of the versatile functional role of PLK-1 in chromosomal segregation, mitosis progression, and organogenesis, its’ participatory role must be studied in other processes, such as neurogenesis, axis patterning, germ layer specification, non-homologous recombination, base and nucleotide excision repair, early birth defects and other neurodegenerative diseases.