Detection of p21WAF1/Cip1 in brain metastases.
The p21WAF1/Cip1 (p21) protein, a negative regulator of G1 checkpoint control, was overexpressed in the majority of human gliomas. To investigate whether p21 expression in brain metastases from various systemic origins is similar to that in gliomas and whether p21 expression is regulated differently in brain metastases and in corresponding primary tumors, we used immunohistochemical staining to examine the expression of p21 in paraffin-embedded sections prepared from primary colon and breast carcinomas and from metastatic brain tumors that originated from colon, breast, lung, and kidney cancers and from melanoma. Our results showed that 56% (28 of 50) of the brain metastases samples have more than 1% p21-positive staining cells compared with 87% of primary gliomas reported previously. Among the samples analyzed, p21 expression in brain metastases from breast carcinomas was much higher than in primary breast carcinomas. In contrast, p21 expression in brain metastases from colon carcinomas was less than primary colon carcinomas. The results from this pilot study suggest that p21 expression is regulated differently in metastatic and primary tumors.
Ruan
S
S
Department of Neuro-Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Fuller
G
G
Levin
V
V
Bruner
J M
JM
Zhang
W
W
D001932:Brain Neoplasms / Q000378:metabolism* / Q000556:secondary*; D001943:Breast Neoplasms / Q000378:metabolism / Q000556:secondary; D002277:Carcinoma / Q000378:metabolism / Q000556:secondary; D003110:Colonic Neoplasms / Q000378:metabolism / Q000556:secondary; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D013194:Staining and Labeling; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53