Stem cell markers: ABCG2 and MCM2 expression in retinoblastoma.
OBJECTIVE
The authors studied the expression of cancer stem cell surface marker, ABCG2, and neural stem cell marker, MCM2, in retinoblastoma and correlated clinicopathologically.


METHODS
Among 39 retinoblastomas, 18 tumours were not subjected to preoperative/postoperative chemotherapy, 15 tumours underwent postoperative chemotherapy, and six tumours had preoperative chemotherapy. There were 20 tumours with no invasion and 19 tumours with invasion of choroid/optic nerve. ABCG2 and MCM2 expression was studied by immunohistochemistry.


RESULTS
ABCG2 was positive in six of six and MCM2 was positive in five of six tumours that had recurred in the orbit or metastasised. ABCG2 was positive in 15/19 tumours with invasion. MCM2 was positive in 16/19 tumours with invasion. Invasive tumours showed higher expression of ABCG2 (p < 0.01) and MCM2 (p < 0.01) proteins. There was no correlation with differentiation and laterality of the tumours. Non-neoplastic retina was positive for ABCG2 and MCM2.


CONCLUSIONS
ABCG2 and MCM2 were expressed more in invasive tumours. Further studies are needed to understand the significance of ABCG2 and MCM2 expression in retinoblastoma.
Mohan
A
A
Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai - 600 006, Tamil Nadu, India.
Kandalam
M
M
Ramkumar
H L
HL
Gopal
L
L
Krishnakumar
S
S
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000032:analysis*; D000293:Adolescent; D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis*; D018797:Cell Cycle Proteins / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007223:Infant; D008297:Male; D064111:Minichromosome Maintenance Complex Component 2; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000032:analysis*; D009687:Nuclear Proteins / Q000032:analysis*; D019572:Retinal Neoplasms / Q000737:chemistry* / Q000188:drug therapy / Q000473:pathology; D012175:Retinoblastoma / Q000737:chemistry* / Q000188:drug therapy / Q000473:pathology; D018709:Statistics, Nonparametric; D013234:Stem Cells / Q000378:metabolism
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C084859:MCM2 protein, human; D064111:Minichromosome Maintenance Complex Component 2