The P16 probe, labelled in red, covers a 193kb region of 9p21.3, extending from 105kb telomeric of P16 gene to 46kb centromeric of CDKN2B. The probe mix also contains a control probe for chromosome 9 (D9Z3, the heterochromatic block at 9q12) labelled in green.
The CDKN2A (cyclin-dependent kinase inhibitor 2A) gene at 9p21 is a tumour suppressor gene that has been shown to be deleted in wide range of human malignancies.
Loss of the CDKN2A gene results in cellular proliferation and dysregulation of pro-apoptotic pathways. There are two proteins produced by the CDKN2A gene: p16INK4a and p14ARF, these protein products have been linked to two tumour suppressor pathways: the RB pathway and the p53 pathway, respectively1.
Deletions of 9p that include the CDKN2A gene are frequently reported in patients with acute lymphoblastic leukaemia (ALL): in approximately 30% of adult B-cell ALLs, 30% of childhood ALLs and up to 50% of T- cell ALLs. In adult B-cell ALL, CDKN2A deletions are frequently acquired in disease progression2,3,4,5.
Deletions including the CDKN2A locus have been reported in up to a third of patients with diffuse large B-cell lymphoma (DLBCL)6 and, in glioma, CDKN2A loss has been implicated with shorter overall survival in WHO grade I-III astrocytomas7.
Losses of the CDKN2A region have also been reported in malignant mesothelioma, melanoma, and bladder cancer8,9,10.
Running our PETS protocol was taking upwards of 5 hours to complete based on the previous SOP. After the technical training visit from CytoCell, we were able to make some tweaks to reduce the protocol time down to just 1 hour and 15 minutes, with the same or better results.
Assistant Genetic Technologist, Leicestershire Genetics Centre, UK