@entity1 AP endonuclease (HAP1) plays a major role in the repair of apurinic/apyrimidinic (AP) sites in cellular DNA. We used immunohistochemistry to examine the expression of HAP1 in normal breast and in 102 primary @entity0 . In normal breast epithelium, HAP1 had a uniformly nuclear localization. However, in lactating glandular epithelium, the expression of HAP1 was predominantly cytoplasmic. In @entity189 , both nuclear and cytoplasmic (44%), cytoplasmic (28%) or nuclear staining (24%) were observed. In four cases (4%), no HAP1 expression was detected. All patterns of expression for HAP1 were demonstrated for @entity513 in situ (DCIS), although comedo-type DCIS were usually accompanied by mostly cytoplasmic staining. Similarly, the HAP1 expression in regions of invasive @entity5 @entity39 was cytoplasmic. Pure nuclear HAP1 expression was significantly correlated with low angiogenesis (P = 0.007) and negative lymph node status (P = 0.001). In contrast, cases with cytoplasmic as well as nuclear staining were associated with poor prognostic factors, such as high angiogenesis (P = 0.03) and node positivity (P = 0.03). The pure nuclear staining may be related to better differentiation, as in normal breast, and hence better prognostic features, and cytoplasmic staining to a more metabolically active phenotype with high protein synthesis, as in lactating breast.

XXXX AP endonuclease 1 (HAP1) protein expression in @entity0 correlates with lymph node status and angiogenesis.

@entity1 :: ('9606', 'Species') :: ['Human'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast carcinomas'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumour'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinomas'] @entity513 :: ('MESH:D044584', 'Disease') :: ['ductal carcinomas']
@entity1 :: (9606,Species) :: ['Human']
