OBJECTIVEIdentification of Rb1 mutations permits accurate genetic counseling. Characterization of the causative mutation in a large low penetrance family is likely to provide important information for tumorigenesis of retinoblastoma(RB).

METHODSQuantitative fluorescent multiplex PCR QFM-PCR technique was used for mutation detection. Long fragment PCR, reverse transcriptase-PCR, subcloning, direct sequencing and Western blotting techniques were used for characterizing the mutation.

RESULTSA deletion covering exons 24 and 25 of Rb gene was found in a large family with 122 members in four generations. Of the 18 carries in the family, only 11 were delivered to either unilateral or bilateral RB. The family has much low-penetrance retinoblastoma, compared with the usual, high-penetrance RB (95%). An extent of 4 kb fragment deletion was detected in genomic deletion of the mutation. cDNA and sequence data showed a 174 bp shorter than the wild type message RNA resulting in an in-frame loss of 58 residues. Further analysis demonstrated the truncated protein expression of 6000 Da shorter than wild type RB1 protein.

CONCLUSIONQFM-PCR technique has enabled the investigators to identify a large deletion covering entire exons 24 and 25 of the Rb1 gene. It is the largest deletion ever found in low penetrance RB families. The characterizations of the mutation in genomic DNA, RNA and protein have provided new evidences which enhance credence to the idea that low penetrance retinoblastoma is caused by only partially functional disable of Rb1. The data will be useful in genetic counseling, particularly significant for the unaffected carriers in RB low penetrance families.

Exons ; Female ; Gene Deletion ; Gene Expression ; Humans ; Male ; Pedigree ; Penetrance ; Retinal Neoplasms ; genetics ; Retinoblastoma ; genetics ; Retinoblastoma Protein ; genetics

The risk of radiotherapy-related secondary cancers in children with constitutional retinoblastoma 1 (RB1) mutations has led to reduced use of external beam radiotherapy (EBRT) for RB. Presently, tumor reduction with chemotherapy with or without focal surgery (chemosurgery) is most commonly undertaken; EBRT is avoided as much as possible and is considered only as the last treatment option prior to enucleation. Nevertheless, approximately 80% of patients are diagnosed at a locally advanced stage, and only 20-25% of early stage RB patients can be cured with a chemosurgery strategy. As a whole, chemotherapy fails in more than two-thirds of eyes with advanced stage disease, requiring EBRT or enucleation. Radiotherapy is still considered necessary for patients with large tumor(s) who are not candidates for chemosurgery but who have visual potential. When radiation therapy is indicated, the lowest possible radiation dose combined with systemic or local chemotherapy and focal surgery may yield the best clinical outcomes in terms of local control and treatment-related toxicity. Proton beam therapy is one EBRT method that can be used for treatment of RB and reduces the radiation dose delivered to the adjacent orbital bone while maintaining an adequate dose to the tumor. To maximize the therapeutic success of treatment of advanced RB, the possibility of integrating radiotherapy at early stages of treatment may need to be discussed by a multidisciplinary team, rather than considering EBRT as only a last treatment option.
Child ; Child, Preschool ; Eye Neoplasms/genetics ; Genes, Retinoblastoma/genetics ; Humans ; Radiotherapy Dosage ; Retinal Neoplasms/*radiotherapy ; Retinoblastoma/genetics/*radiotherapy

OBJECTIVETo study the characteristics of RB1 gene mutations in Chinese patients with retinoblastoma.

METHODSPeripheral blood samples of 35 patients with retinoblastoma were collected and genomic DNA was extracted. Multiplex PCR sequencing was carried out to identify RB1 gene mutations. Parents of 6 probands with RB1 mutations were also enrolled to identify the origins of mutations.

RESULTSFourteen patients were found to have carried germline mutations, among whom 11 had bilateral tumors and 3 had unilateral tumors. Sixteen germline mutations were identified, among which 13 were pathological, which included 5 nonsense mutations (c.1072C > T, c.1333C > T, c.1363C > T, c.1399C > T, c.2501C > A), 4 missense mutations (c.920C > T, c.1346G > A, c.1468G > A, c.1861C > A), 2 frameshift mutations (c.1947delG, c.2403delA) and 2 large fragment deletions (c.139_168 del30, exon 8 deletion). Three were non-pathological mutations, including 2 intronic mutations (c.540-23 dupT, c.2664-10T > A) and 1 silent mutation (c.2192T > A). One carrier was identified among the 6 parents of children carrying a RB1 mutation.

CONCLUSIONScreening for RB1 gene mutations in patients with bilateral or unilateral retinoblastoma can help to identify heritable mutations and provide important clues for genetic counseling and clinical management.

Adult ; Asian Continental Ancestry Group ; genetics ; Child ; Child, Preschool ; China ; Female ; Humans ; Infant ; Male ; Mutation ; Pedigree ; Retinoblastoma ; genetics ; Retinoblastoma Protein ; genetics ; Young Adult

We have analyzed paired samples of genomic DNA from peripheral leukocyte and primary tumor tissue from nine patients with retinoblastoma (RB) and from two RB cell lines, WERI-Rb-1 and Y79, to detect the molecular alterations of the retinoblastoma susceptibility gene (RB-1) and N-myc gene. In Southern analysis, RB-1 deletions in tumor tissues were detected in five patients (56%), one of these revealed a total loss of RB-1. N-myc amplification was found only in one (11.1%) out of nine patients. We also observed a total loss of RB-1 in WERI-Rb-1, and a more than 100-fold amplification of N-myc in Y79. The analysis of the relationship between molecular events and clinical characteristics such as age, sex, tumor laterality did not reveal any specific correlation. These results suggest that genetic backgrounds of RB in Korean patients are quite similar to those of reported cases elsewhere. The high sensitivity of our method in detecting the RB-1 loss indicates that this method can be a useful tool for initially screening a large number of tumors.
Child ; Child, Preschool ; Eye Neoplasms/*genetics ; Female ; *Gene Amplification ; *Gene Deletion ; *Genes, Retinoblastoma ; *Genes, myc ; Humans ; Infant ; Male ; Retinoblastoma/*genetics ; Tumor Cells, Cultured

This study investigated the effect of etoposide, an anticancer chemotherapy drug, on B7-H1 expression in retinoblastoma (Rb) cells and the role of miR-513a-5p in the process. Rb cells were divided into control and etoposide groups. In the etoposide group, cells were treated with etoposide at different concentrations (2.5, 5, 10, 20 and 40 μg/mL) for 24 h. Those given no treatment of etopside served as controls. Reverse transcription polymerase chain reaction (RT-PCR), fluorescence quantitative PCR and flow cytometry were performed to measure the mRNA and protein expression of B7-H1 in Rb cells. The mRNA expression of miR-513a-5p in Rb cells before and after etoposide treatment was also detected by fluorescence quantitative PCR. The miR-513a-5p mimics and the miR-513a-5p inhibitor were transfected into Rb cells separately, and fluorescence quantitative PCR and flow cytometry were used to detect the effect of the miR-513a-5p mimics or inhibitor on B7-H1 expression. TargetScan5.2 was employed to predict the miR-513a-5p binding sites in the 3'-untranslated region of B7-H1 mRNA. Luciferase reporter plasmids carrying this site were prepared and transfected into Rb cells and luciferase activity analyzed. The results showed that etoposide stimulated the mRNA and protein expression of B7-H1 in Rb cells, which reached a maximal level after treatment with 5 μg/mL etoposide (P<0.05). However, miR-513a-5p expression was decreased in Rb cells after etoposide treatment. When the miR-513a-5p inhibitor was added, B7-H1 expression was increased with the concentration of the miR-513a-5p inhibitor (P<0.05). Moreover, B7-H1 expression was decreased gradually with the concentration of the miR-513a-5p mimics increased (P<0.01). Additionally, the miR-513a-5p mimics were found to inhibit the luciferase activity. It was concluded that etoposide can promote B7-H1 expression in Rb cells, which may be associated with chemoresistance. The promoting effect of etoposide on B7-H1 expression can be reversed by miR-513a-5p mimics. MiR-513a-5p inhibits the mRNA and protein expression of B7-H1 via binding to the 3'-UTR of B7-H1 mRNA.
B7-H1 Antigen ; genetics ; Cell Line, Tumor ; Etoposide ; pharmacology ; Gene Expression ; drug effects ; genetics ; Humans ; MicroRNAs ; genetics ; Retinoblastoma ; genetics

OBJECTIVETo screen and clone the novel genes related to cellular proliferation of oral squamous cell carcinoma.

METHODSWe selected the Rb gene as the bait protein gene to construct the fusion bait plasmid of yeast two-hybrid. The whole code sequence of Rb gene was acquired by digestion with restricted enzyme EcoRI and BamH1 and reclaimed from its original vector pGBT9-pRb. After being confirmed by electrophoresis, the Rb gene was cloned into the MCS of the plasmid pGBKT7 to construct a recombined plasmid pGBKT7-pRb and the sequence of the recombined plasmid was detected in company. According to the protocol of yeast two hybrid system III, the competent Y187 yeast was prepared, and transformed with recombined plasmid pGBKT7-pRb. Following that, the toxicity and transcriptional activation of this recombined plasmid pGBKT7-pRb in Y187 yeast were tested.

RESULTSThe sequence of the recombined plasmid was correct compared with the sequence provided in Genbank. The protein could be correctly synthesized in vitro, and no self-activating transcriptional activation and toxicity was observed in Y187 yeast.

CONCLUSIONSThe construction of the recombined plasmid was capable to be used as the fusion bait plasmid in yeast two-hybrid system III, and the recombined Rb-protein could be used as the bait protein successfully.

Carcinoma, Squamous Cell ; genetics ; Genes, Retinoblastoma ; genetics ; Genetic Vectors ; Humans ; Mouth Neoplasms ; genetics ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; Recombination, Genetic ; Retinoblastoma Protein ; biosynthesis ; genetics ; Two-Hybrid System Techniques ; Yeasts ; genetics

It has been well known that the survivors of retinoblastoma are prone to have osteosarcoma. But the secondary tumor usually occurs in bilateral, hereditary type of retinoblastoma. We report one case of osteosarcoma in a survivor of unilateral, sporadic retinoblastoma. A fourteen year old male presented with a painfully swollen distal forearm of 2 month duration. He had enucleated his left eye 10 years ago due to retinoblastoma with no other adjuvant therapy. We managed him with our conventional protocol and identified deletion of Rb gene from his pathological specimen by using the PCR-RFLP method. This result is unusual for unilateral nonhereditable retinoblastoma and may suggest gene level change even in sporadic cases. And Rb gene study may be helpful for unilateral, sporadic retinoblastoma patient in detecting the possibility of late osteosarcoma.
Adolescent ; Base Sequence ; Case Report ; DNA Primers ; *Gene Deletion ; *Genes, Retinoblastoma ; Human ; Magnetic Resonance Imaging ; Male ; Molecular Sequence Data ; Osteosarcoma/complications/*genetics/pathology ; Retinoblastoma/complications/*genetics/pathology ; Support, Non-U.S. Gov't ; Survivors

OBJECTIVETo investigate the value of serum miR-17-92 cluster in the diagnosis of retinoblastoma (RB).

METHODSSerum samples were collected from 20 children with RB and 20 healthy controls. Quantitative real-time PCR was used to measure the expression of miR-17-92 cluster. The expression of miR-17-92 cluster was compared between children with different stages of RB and the changes in the expression of miR-17-92 cluster after multimodality therapy were analyzed. The receiver operating characteristic (ROC) curve was used to investigate the value of serum miR-17-92 cluster in the diagnosis of RB.

RESULTSCompared with the healthy controls, the children with RB had significantly higher relative expression of miR-17-3P, miR-17-5P, miR-18a, and miR-20a in serum (P<0.05), and miR-18a showed the greatest increase. There were no significant differences in the relative expression of miR-19a, miR-19b-1, and miR-92a-1 between children with RB and healthy controls (P>0.05). There were no significant differences in the expression of miR-17-5P, miR-17-3P, miR-18a, and miR-20a between the children with early-to-moderate stage of RB and those with advanced stage of RB (P>0.05), but there were significant reductions after multimodality therapy (P<0.05). In the diagnosis of RB, the areas under the ROC curve (AUCs) for serum miR-17-3P, miR-17-5P, miR-18a, and miR-20a were 0.770, 0.755, 0.828, and 0.665 respectively, and miR-18a had the largest AUC, with a sensitivity of 90% and a specificity of 65%.

CONCLUSIONSmiR-17-3P, miR-17-5P, miR-18a, and miR-20a are highly expressed in the serum of children with RB, and miR-18a may be used as a new marker for the diagnosis of RB.

Biomarkers, Tumor ; blood ; Child, Preschool ; Female ; Humans ; Infant ; Male ; MicroRNAs ; blood ; ROC Curve ; Retinoblastoma ; blood ; diagnosis ; genetics

The research was aimed to detect the expression levels of retinoblastoma protein (pRb) in child acute leukemia cells, and to explore its possible association with leukemia cells cycle, the risk of disease, minimal residual disease (MRD) monitoring and prognosis of B-ALL. Flow cytometry (FCM) was used to detect the expression of pRb in 89 cases of acute leukemia (including 25 AML, 10 T-ALL and 54 B-ALL) and bone marrows from 7 normal children (control group). Meanwhile the cell cycle in some cases was analyzed. The results showed that (1) the FCM could accurately detect the expression of pRb in acute leukemia cells; (2) the high level of pRb expression was frequent in all types of child acute leukemias. In the same case, the expression of pRb was significantly increased in leukemia cells when compared with non-leukemia cells. And no detectable pRb protein was found in partial cases of acute leukemia; (3) there was a close relation between expression of pRb and the cell cycle of leukemia cells, the number of G(1) phase cells in pRb positive case of B-ALL was more than that in pRb negative case (92% vs 77%); (4) in B-ALL, the level of pRb expression in MRD positive group was significantly lower than that in MRD negative group (P < 0.05), but pRb expression was stable in non-leukemia cells during therapy; (5) pRb expression was related to the early response to therapy in B-ALL, the expression of pRb was significantly increased in sensitive group when compared with insensitive group (P < 0.05). It is concluded that high level or absence of pRb expression can be found in child acute leukemia cells. The expression of pRb is positively related to cell cycle of leukemia cells, MRD monitoring and the early response to therapy. In short, the detection of pRb expression level can guide the therapy and the evaluation of prognosis in B-ALL.
Burkitt Lymphoma ; metabolism ; Child ; Female ; Flow Cytometry ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; Male ; Neoplasm, Residual ; Prognosis ; Retinoblastoma Protein ; biosynthesis ; genetics

OBJECTIVEE2F-1 and Rb are involved in cell cycle regulation. This study was to illustrate the mechanism of transformation from benign papillomatosis to ductal carcinoma in situ (DCIS) of the breast in relation to E2F-1 and Rb expression.

METHODSIn situ hybridization (ISH) was used to determinate the expression of E2F-1 and Rb mRNA of mild papillomatosis (MP, n = 40), severe papillomatosis (SP, n = 40) and DCIS (n = 40). Immunohistochemistry (IHC) was used to examine the expression of E2F-1 and Rb protein.

RESULTSThe positive rate of E2F-1 mRNA expression in MP, SP and DCIS was 17.5%, 45.0% and 80.0%, and that of E2F-1 protein expression was 20.0%, 47.5% and 77.5%, respectively. There were significant differences among the three groups (P < 0.01), and between any two groups (P < 0.01). The positive rate of Rb mRNA expression in MP, SP and DCIS was 90.0%, 50.5% and 20.0%, and that of Rb protein expression was 85.0%, 52.5% and 22.5%, respectively, with statistically significant difference similar with that of E2F-1. With the progression of papillomatosis to DCIS, the expression of E2F-1 mRNA and protein increased, while that of Rb decreased. The protein expression by IHC was positively correlated with the mRNA expression by ISH. However, that of E2F-1 was negatively correlated with Rb.

CONCLUSIONE2F-1 and Rb might provide a valuable basis for screening high risk papillomatosis and new target of gene therapy for pre-cancerous lesions of the breast.

Breast Neoplasms ; genetics ; metabolism ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; Cell Cycle Proteins ; biosynthesis ; genetics ; DNA-Binding Proteins ; biosynthesis ; genetics ; E2F Transcription Factors ; E2F1 Transcription Factor ; Female ; Gene Expression Regulation, Neoplastic ; Genes, Retinoblastoma ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Papilloma ; genetics ; metabolism ; Precancerous Conditions ; genetics ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Retinoblastoma Protein ; biosynthesis ; genetics ; Transcription Factors ; biosynthesis ; genetics