Nm23 expression in retinoblastoma.
OBJECTIVE
Nm23 is a metastasis-suppressor protein. Decreased nm23 protein contributes to aggressiveness in many tumors. Nm23 immunoreactivity was studied in retinoblastoma and correlated with differentiation and invasiveness.


METHODS
Immunohistochemistry was performed on 73 formalin-fixed, paraffin-embedded specimens of retinoblastoma. Western blot was conducted to confirm the immunohistochemical study. Prognostic features such as differentiation, invasion of choroid, optic nerve, and orbit, and metastasis were analyzed.


RESULTS
Intense nm23 immunoreactivity was seen in 61% of the retinoblastomas with no invasion and faint nm23 immunoreactivity was seen in 85% of the retinoblastomas with invasion (p < 0.001). Poorly differentiated retinoblastoma showed decreased nm23 immunoreactivity compared to well-differentiated retinoblastomas (p = 0.02). An inverse correlation was observed between invasion of choroid, optic nerve, orbit, and metastasis, and nm23 immunoreactivity. Western blot assays of fresh tumor extracts confirmed the immunohistochemical findings.


CONCLUSIONS
Decreased nm23 immunoreactivity was seen in poorly differentiated retinoblastomas and in retinoblastomas with invasiveness. These findings may lay the groundwork for further studies to better understand the molecular mechanisms and provide a more accurate prediction of invasion and metastasis of retinoblastoma.
Krishnakumar
Subramanian
S
Department of Ocular Pathology, Medical and Vision Research Foundations, Sankara Nethralaya, Chennai, Tamil Nadu, India. drkrishnakumar_2000@yahoo.com
Lakshmi
Amirtha
A
Shanmugam
Mahesh P
MP
Vanitha
K
K
Biswas
Jyotirmay
J
D015153:Blotting, Western; D002454:Cell Differentiation; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D054778:NM23 Nucleoside Diphosphate Kinases; D009361:Neoplasm Invasiveness; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism*; D019572:Retinal Neoplasms / Q000378:metabolism* / Q000473:pathology; D012175:Retinoblastoma / Q000378:metabolism* / Q000473:pathology; D013194:Staining and Labeling
D054778:NM23 Nucleoside Diphosphate Kinases; C517938:NME1 protein, human; D009701:Nucleoside-Diphosphate Kinase