title: Expression of high mobility group A2 protein in retinoblastoma and its association with clinicopathologic features.
abstract: Retinoblastoma (RB) is the commonest primary intraocular tumor in children. Overexpression of the high mobility group (HMG) A2 protein has been observed in a variety of malignant tumors and often correlates with poor prognosis. We studied the expression of HMGA2 in primary tumor samples and correlated with clinicopathologic features such as invasion, differentiation, and laterality of the tumors. Among 64 tumors, there were 29 tumors with invasion of the optic nerve, choroid, and/or orbit and 35 tumors without invasion. HMGA2 immunoreactivity was evaluated on archival paraffin sections and the results confirmed by Western blotting on 12 fresh tumor samples. Among 29 tumors with invasion, HMGA2 was strongly positive (++) in 10 tumors, moderately positive (+) in 11 tumors. Among 35 tumors without invasion, HMGA2 was strongly positive (++) in 6 tumors, moderately positive (+) in 6 tumors. Tumors with invasion showed significantly higher expression of HMGA2 compared with tumors without invasion (P<0.01). Non-neoplastic retina was negative for HMGA2. There was no correlation between HMGA2 expression and differentiation/laterality. Western blotting revealed that 7 tumors were strongly positive, 2 were moderately positive, and 1 was faintly positive for HMGA2. Our study has demonstrated the HMGA2 expression in a large cohort of primary retinoblastoma tumors and its correlation with invasiveness.
authors.affiliation: L and T Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Nalini
authors.initials: N
authors.lastname: Venkatesan
authors.forename: Mallikarjuna
authors.initials: M
authors.lastname: Kandalam
authors.forename: Gunisha
authors.initials: G
authors.lastname: Pasricha
authors.forename: Venil
authors.initials: V
authors.lastname: Sumantran
authors.forename: Guidalberto
authors.initials: G
authors.lastname: Manfioletti
authors.forename: Santa Jeremy
authors.initials: SJ
authors.lastname: Ono
authors.forename: Maddy Ashwin
authors.initials: MA
authors.lastname: Reddy
authors.forename: Subramanian
authors.initials: S
authors.lastname: Krishnakumar
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D015153:Blotting, Western; D002675:Child, Preschool; D005260:Female; D025743:HMGA2 Protein / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D009361:Neoplasm Invasiveness; D011379:Prognosis; D019572:Retinal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D012175:Retinoblastoma / Q000378:metabolism* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D025743:HMGA2 Protein