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

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

Apoptosis ; Brain Neoplasms ; genetics ; pathology ; Cell Proliferation ; Genes, Retinoblastoma ; genetics ; Genes, erbB-1 ; genetics ; Genes, p53 ; genetics ; Glioma ; genetics ; pathology ; Humans ; Inhibitor of Growth Protein 1 ; Intracellular Signaling Peptides and Proteins ; genetics ; Mutation ; Nuclear Proteins ; genetics ; Tumor Suppressor Proteins ; 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

Acute Disease ; Blast Crisis ; genetics ; Genes, Retinoblastoma ; Genes, Wilms Tumor ; Humans ; Leukemia ; genetics ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; pathology ; Polymerase Chain Reaction ; U937 Cells

OBJECTIVEBoth tumor suppressor p16INK4A and p15INK4B are members of INK family of CDK inhibitor. Although the role of p16 has been well documented, the role of p15 and its signaling pathway remain less well studied. This study was aimed to assess the effect of p16 and p15 on hepatocarcinoma cell lines with different status of Rb gene.

METHODSAfter identification of the genetic status of p16, p15 as well as Rb of human hepatocellular carcinoma (HCC) cell lines BEL7402, SMMC7721 with the use of multiple PCR, the eukaryotic expression p16 and p15 recombinants pXJ-p16 and pXJ-p15 were constructed, respectively. The existence of exogenous p16, p15 genes, and the expression of p16 and p15 were assayed by means of PCR and RNA dot blotting. Finally, the proliferation and apoptosis were studied by using MTT, colony formation assay and flow cytometry.

RESULTSNeither deletion of p16 nor p15 was detected in the two cell lines. However, Rb exons 14-16 instead of exons 22-23 deletion existed in SMMC7721. The increased mRNA expression level of p16 was found in BEL7402-p16 and SMMC7721-p16, while increased mRNA expression level of p15 was found in BEL7402-p15. The endogenous p16 and p15 genes were transcripted at low level. The cell growth and colony formation were decreased in BEL7402-p15, compared with either mock cell BEL7402 or vector control cell BEL7402-pXJ. Also shown in this study were an altered G1 phase population from 37.7% to 43.6%, an S phase population from 22% to 13% (P<0.05), and a Sub G1 peak (apoptosis peak) in BEL7402-p15. Conversely, BEL7402-p16 with endogenous p16 gene showed neither difference in cell cycle population nor difference in colony formation rate, compared with control cell groups. Additionally, SMMC7721-p16 cell growth was not inhibited by exogenous p16 gene.

CONCLUSIONp15 significantly arrested cell proliferation and induced apoptosis in BEL7402 in vitro, and the function was not influenced by endogenous p15 gene. The inhibition of cell growth by p16 on HCC cells could be dependent on intact RB pathway.

Apoptosis ; Carcinoma, Hepatocellular ; genetics ; Cell Cycle Proteins ; genetics ; Cell Division ; Cyclin-Dependent Kinase Inhibitor p15 ; Genes, Retinoblastoma ; Genes, Tumor Suppressor ; Genes, p16 ; Humans ; Liver Neoplasms ; genetics ; pathology ; RNA, Messenger ; analysis ; Tumor Suppressor Proteins ; 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 methylation of p16(INK4a) and RB gene, and the expression of p16(INK4a) in meningiomas.

METHODSMethylation-specific polymerase chain reaction (MSP) was used to detect the methylation of p16(INK4a) and RB in 50 cases of meningiomas, and immunostaining was performed to analyze the protein expression of p16(INK4a) in 25 of those cases.

RESULTSNo methylation was found in the benign meningiomas, whereas methylation of p16(INK4a)or RB occurred in 6(37.5%) cases of grade II tumors and 4(28.6%) cases of grade III tumors, and among these cases, an atypical meningioma showed methylation of both genes. Thirteen cases showed p16(INK4a) positive expression, but none of them was methylated.

CONCLUSIONThe methylation of p16(INK4a) or RB is related with the tumorigenesis and progression of atypical and anaplastic meningiomas, and a probable mechanism is that methylation causes the loss of expression and leads to dysfuncation of the p16(INK4a)/cyclin D1/CDK4/RB pathway.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cyclin D1 ; genetics ; Cyclin-Dependent Kinase 4 ; Cyclin-Dependent Kinases ; genetics ; DNA Methylation ; Female ; Genes, Retinoblastoma ; Genes, p16 ; Humans ; Male ; Meningeal Neoplasms ; genetics ; Meningioma ; genetics ; Middle Aged ; Proto-Oncogene Proteins

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

OBJECTIVESTo explore the effects of p210 bcr/abl fusion gene on expression of beta1 integrin and L-selectin mRNAs in mouse chronic myeloid leukemia (CML) cells.

METHODSComparisons of beta1 integrin and L-selectin mRNA levels among p210 bcr/abl negative, p210 bcr/abl positive, and p210 bcr/abl-Rb-C-Box positive cells were undertaken by quantity RT-PCR.

RESULTSIn p210 bcr/abl positive cells, L-selectin mRNA level was decreased, but beta1 integrin mRNA expression had no change as compared to those in p210 bcr/abl negative cells. When inhibition of bcr-abl tyrosine kinase activity by Rb-C-Box, the L-selectin mRNA expression restored to normal (similar to p210 bcr/abl negative cells).

CONCLUSIONp210 bcr/abl oncoprotein inhibits expression of L-selectin mRNA, but not of beta1 integrin mRNA.

Animals ; Cell Line, Tumor ; Fusion Proteins, bcr-abl ; genetics ; Gene Expression Regulation, Leukemic ; Genes, Retinoblastoma ; genetics ; Integrin beta1 ; genetics ; L-Selectin ; genetics ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Mice ; RNA, Messenger ; genetics ; Transfection