Gene Symbol: Cdkn1b
Description: cyclin-dependent kinase inhibitor 1B
Alias: AA408329, AI843786, Kip1, p27, p27Kip1, cyclin-dependent kinase inhibitor 1B, cyclin-dependent kinase inhibitor p27
Species: mouse
Products:     Cdkn1b

Top Publications

  1. Livne Bar I, Pacal M, Cheung M, Hankin M, Trogadis J, Chen D, et al. Chx10 is required to block photoreceptor differentiation but is dispensable for progenitor proliferation in the postnatal retina. Proc Natl Acad Sci U S A. 2006;103:4988-93 pubmed
    ..only a small fraction of cells expressing mutated Chx10 mRNA were rods, but this fraction increased after p27(Kip1) inactivation, which partially rescues proliferation...
  2. Muzumdar M, Luo L, Zong H. Modeling sporadic loss of heterozygosity in mice by using mosaic analysis with double markers (MADM). Proc Natl Acad Sci U S A. 2007;104:4495-500 pubmed
    ..As proof of principle, we studied the consequence of sporadic loss of p27kip1, a cyclin-dependent kinase inhibitor...
  3. Defoe D, Adams L, Sun J, Wisecarver S, Levine E. Defects in retinal pigment epithelium cell proliferation and retinal attachment in mutant mice with p27(Kip1) gene ablation. Mol Vis. 2007;13:273-86 pubmed
    ..The present study examines the potential role of the negative cell cycle regulator p27(Kip1) in controlling RPE proliferation, using mice with targeted ablation of the p27(Kip1) gene...
  4. Grimmler M, Wang Y, Mund T, Cilensek Z, Keidel E, Waddell M, et al. Cdk-inhibitory activity and stability of p27Kip1 are directly regulated by oncogenic tyrosine kinases. Cell. 2007;128:269-80 pubmed
    b>p27Kip1 controls cell proliferation by binding to and regulating the activity of cyclin-dependent kinases (Cdks). Here we show that Cdk inhibition and p27 stability are regulated through direct phosphorylation by tyrosine kinases...
  5. Timmerbeul I, Garrett Engele C, Kossatz U, Chen X, Firpo E, Grünwald V, et al. Testing the importance of p27 degradation by the SCFskp2 pathway in murine models of lung and colon cancer. Proc Natl Acad Sci U S A. 2006;103:14009-14 pubmed
    Decreased expression of the CDK inhibitor p27kip1 in human tumors directly correlates with increased resistance to chemotherapies, increased rates of metastasis, and an overall increased rate of patient mortality...
  6. Pippa R, Espinosa L, Gundem G, García Escudero R, Dominguez A, Orlando S, et al. p27Kip1 represses transcription by direct interaction with p130/E2F4 at the promoters of target genes. Oncogene. 2012;31:4207-20 pubmed publisher
    The cyclin-cdk (cyclin-dependent kinase) inhibitor p27Kip1 (p27) has a crucial negative role on cell cycle progression...
  7. See W, Heinberg A, Holland E, Resh M. p27 deficiency is associated with migration defects in PDGF-expressing gliomas in vivo. Cell Cycle. 2010;9:1562-7 pubmed
    p27(Kip1) is a cyclin dependent kinase inhibitor that functions as a tumor suppressor in a variety of different cancers...
  8. Zhao H, Bauzon F, Fu H, Lu Z, Cui J, Nakayama K, et al. Skp2 deletion unmasks a p27 safeguard that blocks tumorigenesis in the absence of pRb and p53 tumor suppressors. Cancer Cell. 2013;24:645-59 pubmed publisher
    ..Here, we found that p53 activates expression of Pirh2 and KPC1, two of the three ubiquitin ligases for p27. Loss of p53 in the absence of Skp2, the third ubiquitin ligase for p27, shrinks the cellular pool of p27 ubiquitin ..
  9. Le T, Wroblewski E, Patel S, Riesenberg A, Brown N. Math5 is required for both early retinal neuron differentiation and cell cycle progression. Dev Biol. 2006;295:764-78 pubmed
    ..The drastic fate shift of Math5-/- cells correlates with age-specific alterations in p27/Kip1 expression and an inability to become fully postmitotic...

More Information


  1. Monahan P, Himes A, Parfieniuk A, Raetzman L. p21, an important mediator of quiescence during pituitary tumor formation, is dispensable for normal pituitary development during embryogenesis. Mech Dev. 2012;128:640-52 pubmed publisher
    ..The cyclin dependent kinase inhibitors (CDKIs) of the CIP/KIP family, p21, p27 and p57, mediate cell cycle inhibition...
  2. Dong Y, Sui L, Yamaguchi F, Kamitori K, Hirata Y, Hossain M, et al. Phosphatase and tensin homolog deleted on chromosome 10 regulates sensory cell proliferation and differentiation of hair bundles in the mammalian cochlea. Neuroscience. 2010;170:1304-13 pubmed publisher
  3. Nguyen L, Besson A, Heng J, Schuurmans C, Teboul L, Parras C, et al. p27kip1 independently promotes neuronal differentiation and migration in the cerebral cortex. Genes Dev. 2006;20:1511-24 pubmed
    ..Here we show that the cyclin-dependent kinase inhibitor p27(Kip1) plays an important role in neurogenesis in the mouse cerebral cortex by promoting the differentiation and radial ..
  4. Monahan P, Rybak S, Raetzman L. The notch target gene HES1 regulates cell cycle inhibitor expression in the developing pituitary. Endocrinology. 2009;150:4386-94 pubmed publisher
    ..Hes1 have increased cell cycle exit, shown by significant increases in the cyclin-dependent kinase inhibitors, p27 and p57, from e10.5 to e14.5...
  5. Miranda Carboni G, Krum S, Yee K, Nava M, Deng Q, Pervin S, et al. A functional link between Wnt signaling and SKP2-independent p27 turnover in mammary tumors. Genes Dev. 2008;22:3121-34 pubmed publisher
    Loss of the CDK inhibitor p27(KIP1) is widely linked with poor prognosis in human cancer...
  6. Lavine K, Schmid G, Smith C, Ornitz D. Novel tool to suppress cell proliferation in vivo demonstrates that myocardial and coronary vascular growth represent distinct developmental programs. Dev Dyn. 2008;237:713-24 pubmed publisher
    ..We have generated mice that conditionally express the cell cycle inhibitor p27(Kip1), following Cre-mediated recombination, as a tool to separate tissue proliferation from other cellular processes...
  7. Das G, Choi Y, Sicinski P, Levine E. Cyclin D1 fine-tunes the neurogenic output of embryonic retinal progenitor cells. Neural Dev. 2009;4:15 pubmed publisher
    ..Replacement with cyclin E or inactivation of cyclin-dependent kinase inhibitor p27Kip1 restores the balance of RPCs and retinal cell types to more normal distributions, which suggests that regulation ..
  8. Zhao H, Yang T, Madakashira B, Thiels C, Bechtle C, Garcia C, et al. Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation. Dev Biol. 2008;318:276-88 pubmed publisher
    ..abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27(kip1) and p57(kip2), increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and alpha-,..
  9. Matsumoto A, Takeishi S, Kanie T, Susaki E, Onoyama I, Tateishi Y, et al. p57 is required for quiescence and maintenance of adult hematopoietic stem cells. Cell Stem Cell. 2011;9:262-71 pubmed publisher
    ..Members of the Cip/Kip family of cyclin-dependent kinase (CDK) inhibitors (p21, p27, p57) have been implicated in HSC quiescence, but loss of p21 or p27 in mice affects HSC quiescence or ..
  10. Gui H, Li S, Matise M. A cell-autonomous requirement for Cip/Kip cyclin-kinase inhibitors in regulating neuronal cell cycle exit but not differentiation in the developing spinal cord. Dev Biol. 2007;301:14-26 pubmed
    ..both distinct and overlapping populations of nascent and post-mitotic neurons during early neurogenesis, with p27(Kip1) having the broadest expression, and both p57(Kip2) and p21(Cip1) showing transient expression in restricted ..
  11. Lu Z, Marcelin G, Bauzon F, Wang H, Fu H, Dun S, et al. pRb is an obesity suppressor in hypothalamus and high-fat diet inhibits pRb in this location. EMBO J. 2013;32:844-57 pubmed publisher
    ..In contrast, deleting Rb1 in the antagonizing AGRP/NPY neurons shows no effects. Thus, pRb-E2F1 is an obesity suppression mechanism in ARC POMC neurons and HFD-AMPK inhibits this mechanism by phosphorylating pRb in this location. ..
  12. Donovan S, Schweers B, Martins R, Johnson D, Dyer M. Compensation by tumor suppressor genes during retinal development in mice and humans. BMC Biol. 2006;4:14 pubmed
    ..Together, these data suggest a model that explains why humans are susceptible to retinoblastoma following RB1 loss, but mice require both Rb and p107 gene inactivation. ..
  13. Langenickel T, Olive M, Boehm M, San H, Crook M, Nabel E. KIS protects against adverse vascular remodeling by opposing stathmin-mediated VSMC migration in mice. J Clin Invest. 2008;118:3848-59 pubmed publisher
    ..KIS) targets 2 key regulators of cell proliferation and migration, the cyclin-dependent kinase inhibitor p27Kip1 and the microtubule-destabilizing protein stathmin...
  14. Zhao X, D Arca D, Lim W, Brahmachary M, Carro M, Ludwig T, et al. The N-Myc-DLL3 cascade is suppressed by the ubiquitin ligase Huwe1 to inhibit proliferation and promote neurogenesis in the developing brain. Dev Cell. 2009;17:210-21 pubmed publisher
    ..Our results indicate that Huwe1 balances proliferation and neurogenesis in the developing brain and that this pathway is subverted in malignant brain tumors. ..
  15. Besson A, Hwang H, Cicero S, Donovan S, Gurian West M, Johnson D, et al. Discovery of an oncogenic activity in p27Kip1 that causes stem cell expansion and a multiple tumor phenotype. Genes Dev. 2007;21:1731-46 pubmed
    The cell cycle inhibitor p27Kip1 also has cyclin-cyclin-dependent kinase (CDK)-independent functions...
  16. Ohyama T, Basch M, Mishina Y, Lyons K, Segil N, Groves A. BMP signaling is necessary for patterning the sensory and nonsensory regions of the developing mammalian cochlea. J Neurosci. 2010;30:15044-51 pubmed publisher
    ..Our results suggest BMP signaling is required for patterning sensory and nonsensory tissue in the mammalian cochlea. ..
  17. Wang H, Bauzon F, Ji P, Xu X, Sun D, Locker J, et al. Skp2 is required for survival of aberrantly proliferating Rb1-deficient cells and for tumorigenesis in Rb1+/- mice. Nat Genet. 2010;42:83-8 pubmed publisher
    ..Eliminating p27 phosphorylation on T187 in p27T187A knock-in mice reproduces the effects of Skp2 knockout, identifying p27 ..
  18. Bilodeau S, Roussel Gervais A, Drouin J. Distinct developmental roles of cell cycle inhibitors p57Kip2 and p27Kip1 distinguish pituitary progenitor cell cycle exit from cell cycle reentry of differentiated cells. Mol Cell Biol. 2009;29:1895-908 pubmed publisher
    ..Upon differentiation, p57(Kip2) is replaced by p27(Kip1)...
  19. Bhatia B, Malik A, Fernandez L A, Kenney A. p27(Kip1), a double-edged sword in Shh-mediated medulloblastoma: Tumor accelerator and suppressor. Cell Cycle. 2010;9:4307-14 pubmed
    ..In mitogen-stimulated cells, nuclear localized cyclin dependent kinase (cdk) inhibitor p27 (Kip1) functions as a checkpoint control at the G1- to S-phase transition by inhibiting cdk2...
  20. Cook M, Munger S, Nadeau J, Capel B. Regulation of male germ cell cycle arrest and differentiation by DND1 is modulated by genetic background. Development. 2011;138:23-32 pubmed publisher
    ..that DND1 directly binds a group of transcripts that encode negative regulators of the cell cycle, including p27(Kip1) and p21(Cip)(1)...
  21. Hu L, Ibrahim S, Liu C, Skaar J, Pagano M, Karpatkin S. Thrombin induces tumor cell cycle activation and spontaneous growth by down-regulation of p27Kip1, in association with the up-regulation of Skp2 and MiR-222. Cancer Res. 2009;69:3374-81 pubmed publisher
    ..Cell cycle kinases and inhibitors in synchronized tumor cells revealed high levels of p27(Kip1) and low levels of Skp2 and cyclins D1 and A...
  22. Dabdoub A, Puligilla C, Jones J, Fritzsch B, Cheah K, Pevny L, et al. Sox2 signaling in prosensory domain specification and subsequent hair cell differentiation in the developing cochlea. Proc Natl Acad Sci U S A. 2008;105:18396-401 pubmed publisher
    ..These results demonstrate crucial and diverse roles for Sox2 in the development, specification, and maintenance of sensory cells within the cochlea. ..
  23. Singh A, Jatzek A, Plisch E, Srinivasan R, Svaren J, Suresh M. Regulation of memory CD8 T-cell differentiation by cyclin-dependent kinase inhibitor p27Kip1. Mol Cell Biol. 2010;30:5145-59 pubmed publisher
    ..Here, we have identified the cyclin-dependent kinase inhibitor p27(Kip1) as a critical regulator of the CD8 T-cell homeostasis at all phases of the T-cell response to an acute viral ..
  24. Zou P, Yoshihara H, Hosokawa K, Tai I, Shinmyozu K, Tsukahara F, et al. p57(Kip2) and p27(Kip1) cooperate to maintain hematopoietic stem cell quiescence through interactions with Hsc70. Cell Stem Cell. 2011;9:247-61 pubmed publisher
    ..proceeded normally in HSCs null for cyclin-dependent kinase (CDK) inhibitor p57 due to compensatory upregulation of p27. HSCs null for both p57 and p27, however, were more proliferative and had reduced capacity to engraft in ..
  25. Huh S, Jones J, Warchol M, Ornitz D. Differentiation of the lateral compartment of the cochlea requires a temporally restricted FGF20 signal. PLoS Biol. 2012;10:e1001231 pubmed publisher
    ..The viability and hearing loss in Fgf20 knockout mice suggest that FGF20 may also be a deafness-associated gene in humans. ..
  26. Yamamoto N, Okano T, Ma X, Adelstein R, Kelley M. Myosin II regulates extension, growth and patterning in the mammalian cochlear duct. Development. 2009;136:1977-86 pubmed publisher
    ..Our results also provide insights into the cellular mechanisms that are required for the formation of highly ordered cellular patterns...
  27. Hayashi T, Ray C, Bermingham McDonogh O. Fgf20 is required for sensory epithelial specification in the developing cochlea. J Neurosci. 2008;28:5991-9 pubmed publisher
    ..Our results thus define the period of FGF-dependent sensory cell specification and the ligand that mediates this step in cochlear development. ..
  28. Garcia Fernandez R, Garcia Palencia P, Sánchez M, Gil Gomez G, Sanchez B, Rollan E, et al. Combined loss of p21(waf1/cip1) and p27(kip1) enhances tumorigenesis in mice. Lab Invest. 2011;91:1634-42 pubmed publisher
    The cell cycle inhibitors p21(Waf1/Cip1) and p27(Kip1) are frequently downregulated in many human cancers, and correlate with a worse prognosis...
  29. Poche R, Kwan K, Raven M, Furuta Y, Reese B, Behringer R. Lim1 is essential for the correct laminar positioning of retinal horizontal cells. J Neurosci. 2007;27:14099-107 pubmed
    ..This study is the first to describe a cell type-specific genetic program that is essential for targeting a discrete retinal neuron population to the proper lamina. ..
  30. Liu J, Zhang D, Mi X, Xia Q, Yu Y, Zuo Z, et al. p27 suppresses arsenite-induced Hsp27/Hsp70 expression through inhibiting JNK2/c-Jun- and HSF-1-dependent pathways. J Biol Chem. 2010;285:26058-65 pubmed publisher
    b>p27 is an atypical tumor suppressor that can regulate the activity of cyclin-dependent kinases and G(0)-to-S phase transitions...
  31. Zhang D, Wang Y, Liang Y, Zhang M, Wei J, Zheng X, et al. Loss of p27 upregulates MnSOD in a STAT3-dependent manner, disrupts intracellular redox activity and enhances cell migration. J Cell Sci. 2014;127:2920-33 pubmed publisher
    ..The modulation of cell migration by p27 (officially known as CDKN1B) has been reported, but the exact mechanism(s) whereby p27 interacts with downstream effectors that control cell ..
  32. Zhou W, Yang Q, Low C, Karthik B, Wang Y, Ryo A, et al. Pin1 catalyzes conformational changes of Thr-187 in p27Kip1 and mediates its stability through a polyubiquitination process. J Biol Chem. 2009;284:23980-8 pubmed publisher
    ..The phosphorylation-directed ubiquitination is one of the major mechanisms to regulate the abundance of p27(Kip1)...
  33. Li H, Collado M, Villasante A, Matheu A, Lynch C, Canamero M, et al. p27(Kip1) directly represses Sox2 during embryonic stem cell differentiation. Cell Stem Cell. 2012;11:845-52 pubmed publisher
    ..We have observed that cells lacking the tumor suppressor p27 can be reprogrammed into induced pluripotent stem cells (iPSCs) in the absence of ectopic Sox2...
  34. Majumder P, Grisanzio C, O Connell F, Barry M, Brito J, Xu Q, et al. A prostatic intraepithelial neoplasia-dependent p27 Kip1 checkpoint induces senescence and inhibits cell proliferation and cancer progression. Cancer Cell. 2008;14:146-55 pubmed publisher
    ..In luminal epithelial cells of Akt-driven PIN, we show the concomitant induction of p27(Kip1) and senescence...
  35. Garrett Engele C, Tasch M, Hwang H, Fero M, Perlmutter R, Clurman B, et al. A mechanism misregulating p27 in tumors discovered in a functional genomic screen. PLoS Genet. 2007;3:e219 pubmed
    The cyclin-dependent kinase inhibitor p27(KIP1) is a tumor suppressor gene in mice, and loss of p27 protein is a negative prognostic indicator in human cancers. Unlike other tumor suppressors, the p27 gene is rarely mutated in tumors...
  36. Elshatory Y, Deng M, Xie X, Gan L. Expression of the LIM-homeodomain protein Isl1 in the developing and mature mouse retina. J Comp Neurol. 2007;503:182-97 pubmed
    ..Taken together, Isl1 is expressed during the maturation of and is later maintained in retinal ganglion cells and subtypes of amacrine and bipolar cells where it may function in the maintenance of these cells into adulthood. ..
  37. Yamamoto N, Chang W, Kelley M. Rbpj regulates development of prosensory cells in the mammalian inner ear. Dev Biol. 2011;353:367-79 pubmed publisher
    ..of developing cochleae in Rbpj-mutants indicates changes in the spatiotemporal patterns of expression for p27(kip1), Atoh1 and hair cell differentiation markers implicating notch signaling in the regulation of the timing of ..
  38. Li X, Tang X, Jablonska B, Aguirre A, Gallo V, Luskin M. p27(KIP1) regulates neurogenesis in the rostral migratory stream and olfactory bulb of the postnatal mouse. J Neurosci. 2009;29:2902-14 pubmed publisher
    ..We investigated the role of p27(KIP1) in regulating cell proliferation and survival in the RMS and olfactory bulb between postnatal day 1 (P1) and P14, ..
  39. Evans Anderson H, Alfieri C, Yutzey K. Regulation of cardiomyocyte proliferation and myocardial growth during development by FOXO transcription factors. Circ Res. 2008;102:686-94 pubmed publisher
    ..5 because of severe myocardial defects that coincide with premature activation of p21(cip1), p27(kip1), and p57(kip2) and decreased myocyte proliferation...
  40. Suzuki S, Fukasawa H, Kitagawa K, Uchida C, Hattori T, Isobe T, et al. Renal damage in obstructive nephropathy is decreased in Skp2-deficient mice. Am J Pathol. 2007;171:473-83 pubmed
    Ubiquitin-dependent degradation of the cyclin-dependent kinase inhibitor p27 mediated by SCF-Skp2 ubiquitin ligase is involved in cell cycle regulation...
  41. Georgia S, Soliz R, Li M, Zhang P, Bhushan A. p57 and Hes1 coordinate cell cycle exit with self-renewal of pancreatic progenitors. Dev Biol. 2006;298:22-31 pubmed
  42. Serres M, Zlotek Zlotkiewicz E, Concha C, Gurian West M, Daburon V, Roberts J, et al. Cytoplasmic p27 is oncogenic and cooperates with Ras both in vivo and in vitro. Oncogene. 2011;30:2846-58 pubmed publisher
    p27(Kip1) (p27) can have opposing roles during malignant transformation depending on cellular context: on one hand it functions as a tumor suppressor by inhibiting cyclin-cyclin-dependent kinase (CDK) activity in the nucleus and on the ..
  43. Itoh Y, Masuyama N, Nakayama K, Nakayama K, Gotoh Y. The cyclin-dependent kinase inhibitors p57 and p27 regulate neuronal migration in the developing mouse neocortex. J Biol Chem. 2007;282:390-6 pubmed
    ..We have proposed in this study that the cdk inhibitors p57 and p27 play a role in this coordination...
  44. Lee Y, Liu F, Segil N. A morphogenetic wave of p27Kip1 transcription directs cell cycle exit during organ of Corti development. Development. 2006;133:2817-26 pubmed
    ..The mammalian cyclin-dependent kinase inhibitor p27(Kip1) is required for the correct timing of cell cycle exit in developing tissues, and thus plays a crucial role in this ..
  45. Berthet C, Klarmann K, Hilton M, Suh H, Keller J, Kiyokawa H, et al. Combined loss of Cdk2 and Cdk4 results in embryonic lethality and Rb hypophosphorylation. Dev Cell. 2006;10:563-73 pubmed
    ..In contrast, loss of p27 did not rescue Cdk2-/- Cdk4-/- phenotypes...
  46. Old J, Kratzat S, Hoellein A, Graf S, Nilsson J, Nilsson L, et al. Skp2 directs Myc-mediated suppression of p27Kip1 yet has modest effects on Myc-driven lymphomagenesis. Mol Cancer Res. 2010;8:353-62 pubmed publisher
    The universal cyclin-dependent kinase inhibitor p27(Kip1) functions as a tumor suppressor, and reduced levels of p27(Kip1) connote poor prognosis in several human malignancies...
  47. Belletti B, Pellizzari I, Berton S, Fabris L, Wolf K, Lovat F, et al. p27kip1 controls cell morphology and motility by regulating microtubule-dependent lipid raft recycling. Mol Cell Biol. 2010;30:2229-40 pubmed publisher
    p27(kip1) (p27) is an inhibitor of cyclin/cyclin-dependent kinase complexes, whose nuclear loss indicates a poor prognosis in various solid tumors...
  48. Iulianella A, Sharma M, Durnin M, Vanden Heuvel G, Trainor P. Cux2 (Cutl2) integrates neural progenitor development with cell-cycle progression during spinal cord neurogenesis. Development. 2008;135:729-41 pubmed publisher
    ..defects correlate with reduced cell-cycle progression of neural progenitors coupled with diminished Neurod and p27(Kip1) activity...
  49. Spiller C, Wilhelm D, Koopman P. Retinoblastoma 1 protein modulates XY germ cell entry into G1/G0 arrest during fetal development in mice. Biol Reprod. 2010;82:433-43 pubmed publisher
    ..Rbl1 and Rbl2 in the Rb1(-/-) testes, but we saw a significant increase of cyclin-dependent kinase (CDK) inhibitor Cdkn1b and Cdkn2b expression...
  50. Berton S, Belletti B, Wolf K, Canzonieri V, Lovat F, Vecchione A, et al. The tumor suppressor functions of p27(kip1) include control of the mesenchymal/amoeboid transition. Mol Cell Biol. 2009;29:5031-45 pubmed publisher
    In many human cancers, p27 downregulation correlates with a worse prognosis, suggesting that p27 levels could represent an important determinant in cell transformation and cancer development...
  51. Bermingham McDonogh O, Oesterle E, Stone J, Hume C, Huynh H, Hayashi T. Expression of Prox1 during mouse cochlear development. J Comp Neurol. 2006;496:172-86 pubmed
    ..These studies form a baseline from which we can analyze the role of Prox1 in vertebrate sensory development. ..
  52. Keller U, Old J, Dorsey F, Nilsson J, Nilsson L, Maclean K, et al. Myc targets Cks1 to provoke the suppression of p27Kip1, proliferation and lymphomagenesis. EMBO J. 2007;26:2562-74 pubmed
    Reduced levels of the cyclin-dependent kinase inhibitor p27(Kip1) connote poor prognosis in cancer...
  53. Martins R, Zindy F, Donovan S, Zhang J, Pounds S, Wey A, et al. N-myc coordinates retinal growth with eye size during mouse development. Genes Dev. 2008;22:179-93 pubmed publisher
    ..N-myc represses the expression of the cyclin-dependent kinase inhibitor p27Kip1 but acts independently of cyclin D1, the major D-type cyclin in the developing mouse retina...