Springer, Encyclopedic Reference Of Cancer (2001) Ocr 7.0 Lotb.pdf

704 Ploidy
Ploidy
Definition
Ploidy refers to the number of copies of the
chromosome set present in a cell; a haploid
cell has one copy and a diploid has two copies.
PLZF
Definition
PLZF is a smooth muscle myosin heavy chain
disrupted by the ! inv(16).
PML Nuclear Bodies
Definition
PML nuclear bodies are nuclear structures that
are disrupted in acute promyelocytic leukemia
and by certain viruses, which are the repository
for several proteins.
PMS1
Definition
Postmeiotic segregation increased (S.cerevisiae)
1 (PMS1), also known as PMSL1, is a protein
of 932 aa and 105 kD that is involved in
mismatch repair of DNA. Mutations in PMS1
are associated with familial nonpolyposis colon
cancer (! HNPCC) (! Lynch syndrome), and the
gene locus maps to 2q31-33.
PMS2
Definition
Postmeiotic segregation increased (S. cerevisiae)
2 (PMS2), also known as PMSL2, is a pro-
tein of 862 aa and 95 kD that is involved in mismatch
repair of DNA, and interacts with
! MLH1. Mutations in PMS2 are associated
with familial hereditary nonpolyposis colon
cancer (! HNPCC) (! Lynch syndrome), and
the gene locus maps to 7p22.
PMSL1
Definition
! PMS1.
PMSL2
Definition
! PMS2.
PNET
Definition
Primitive neuroectodermal tumor (PNET) are
tumors composed of small densely packed hyperchromatic
cells found in the CNS (central
PNET) or originating from soft tissue and
bone (peripheral PNET). Peripheral PNET are
genetically characterized by a translocation
t(11;22)(q24;q12), are of neural crest origin
and grouped with the ! Ewing sarcoma family
of tumors. Central PNET do not show a
t(11;22) translocation and exhibit divergent differentiation
patterns along neuronal (e.g. cerebral
neuroblastoma) or ependymal (e.g. ependymoblastoma)
lines, or are found in locations
above the cerebellar tentorium (connective tissue
covering the dorsal surface of the cerebellum)
(e.g. pineoblastoma). Medulloblastomas
are infratentorial (infra = below) central
PNETs.