Other tumor-suppressor genes that are exceptions to the " two-hit " rule are those that exhibit haploinsufficiency, including PTCH in medulloblastoma and NF1 in neurofibroma.
32.
It is unknown at this time why, if both types of Schwann cells exhibit bilallelic inactivation of the NF1 gene, only the nonmyelinating variety give rise to neurofibromas.
33.
The latter had, through the years, been variously described as Bizarre cutaneous neurofibroma, Myxoma of nerve sheath, and Pacinian neurofibroma .
34.
The latter had, through the years, been variously described as Bizarre cutaneous neurofibroma, Myxoma of nerve sheath, and Pacinian neurofibroma .
35.
While one defective allele may be inherited, loss of heterozygosity ( LOH ) must occur before a neurofibroma can form; this is called the two-hit hypothesis.
36.
The formation of malignant cancers from neurofibromas is associated with the loss of expression of the CDKN2A or TP53 gene in non-myelinating Schwann cells that also exhibit biallelic inactivation of the NF1 gene.
37.
The grants cover an array of studies, from the genetics of triple-negative breast cancer to imaging of precancerous pancreatic lesions; from neurofibroma tumorigenesis and therapy to the molecular mechanisms of the body s natural killer cells against multiple myeloma; from the role of the ATF3 gene in the development and treatment of chronic lymphocytic leukemia to genomic aberrations driving metastatic squamous cell carcinoma ( a type of skin cancer ).
38.
In tumors, CD34 is found in alveolar soft part sarcoma, preB-ALL ( positive in 75 % ), AML ( 40 % ), AML-M7 ( most ), dermatofibrosarcoma protuberans, gastrointestinal stromal tumors, giant cell fibroblastoma, granulocytic sarcoma, Kaposi s sarcoma, liposarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumors, mengingeal hemangiopericytomas, meningiomas, neurofibromas, schwannomas, and papillary thyroid carcinoma.
39.
Axillary freckling also occurs in other disease processes that closely resemble NF1, such as Legius syndrome ( cafe-au-lait spots, axillary freckling, and macrocephaly without Lisch nodules, neurofibromas or CNS tumors ), and, homozygous HNPCC mutations ( cafe-au-lait spots, axillary freckling, and cutaneous neurofibromas in the setting of Hereditary Non-Polyposis Colon Cancer, also known as Lynch syndrome; seen with family history of HNPCC and consanguinity)
40.
Axillary freckling also occurs in other disease processes that closely resemble NF1, such as Legius syndrome ( cafe-au-lait spots, axillary freckling, and macrocephaly without Lisch nodules, neurofibromas or CNS tumors ), and, homozygous HNPCC mutations ( cafe-au-lait spots, axillary freckling, and cutaneous neurofibromas in the setting of Hereditary Non-Polyposis Colon Cancer, also known as Lynch syndrome; seen with family history of HNPCC and consanguinity)
