SHMT2 and cervical squamous intraepithelial neoplasia: ARL2, BUB3, DSN1, NUF2 and SPC24 encode functions in mitosis with specific roles in mitotic spindle assembly, microtubule dynamics, and kinetochore-microtubule attachments [10,11,12], while GART (de novo purine biosynthesis [13]), SHMT2 (de novo thymidylate biosynthesis [14]), GARS (glycyl-tRNA synthesis [15]), PIGS (GPI-anchor biosynthesis [16]) and SKP1 (ubiquitin-mediated proteasomal degradation [17]) encode functions that are not immediately linked to CIN and were purposefully selected to gain insight into novel mechanisms responsible for CIN.