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

OBJECTIVES: The inactivation of the tumor suppressor gene p16INK4a plays an important role in the development of malignant tumors, including oral squamous cell carcinoma. The p16 gene is involved in the p16/cyclin-dependent kinase/retinoblastoma (Rb) gene pathway of cell cycle control. The p16 protein is considered a negative regulator of this pathway. The p16 gene encodes an inhibitor of cyclin-dependent kinases 4 and 6 which regulate the phosphorylation of the retinoblastoma gene and G1 to S phase transition in the cell cycle. However, the p16 gene can lose its functionality through point mutations, loss of heterozygosity or methylation of its promoter region. MATERIALS AND METHODS: In this study, the authors analyzed the correlation between various clinicopathological findings-patient age, gender and smoking, disease recurrence, tumor size, stage, and differentiation- and p16 protein expression or p16 promoter hypermethylation in 59 cases of head and neck squamous cell carcinoma. RESULTS: The results revealed p16 protein expression and p16 promoter hypermethylation in 28 cases (47.5%) and 21 cases (35.6%), respectively, of head and neck squamous cell carcinoma. However, neither p16 protein expression nor p16 promoter hypermethylation had any statistical influence on clinicopathological findings or survival rate. CONCLUSION: This data, and a review of the literature, suggest that p16 promoter hypermethylation cannot yet be used as an independent prognostic factor influencing carcinogenesis, but must be considered as an important factor along with other genetic alterations affecting the pRb pathway.
Carcinoma, Squamous Cell ; Cell Cycle ; Cell Cycle Checkpoints ; Cyclin-Dependent Kinases ; Epigenomics ; Genes, p16 ; Genes, Retinoblastoma ; Genes, Tumor Suppressor ; Head ; Humans ; Loss of Heterozygosity ; Methylation ; Neck ; Phosphorylation ; Point Mutation ; Prognosis ; Recurrence ; S Phase ; Smoke ; Smoking

Objective: To detect and characterize retinoblastoma susceptibility gene (RB1) mutations in tumor samples collected from Filipino patients with retinoblastoma. Methods: Six tumor samples were obtained from Filipino patients diagnosed with retinoblastoma. DNA was extracted from the tumor samples and exons 13-21 of the RB1 gene were amplified by polymerase chain reaction (PCR). PCR amplification products were subsequently purified and sequenced. Mutation detection and characterization were done by alignment of obtained sequences to the RB1 reference sequence from NCBI GenBank using Bioedit® software. The identified mutations were correlated with clinical presentation and family history. These mutations were also compared to known mutations reported in the RB1 Gene Mutation Leiden Open Variation Database (LOVD). Results: Mutations were detected in two out of the six samples. In a patient with unilateral disease and no family history, two mutations were identified: a novel CGT>AGT (Arginine → Serine) missense mutation in position c.1861 of exon 19 and a previously reported CGA>TGA (Arginine → STOP) nonsense mutation in position c. 1735 of exon 18. A possible large exonic deletion was identified in a case of unilateral disease with no family history. Conclusion We were able to identify both novel and known mutations in the RB1 gene of Filipino retinoblastoma cases using DNA sequencing techniques. These techniques may be applied to further characterize the genetic mutations of Filipino retinoblastoma cases and their families in developing a rational method of genetic testing for early diagnosis and counseling.
Retinoblastoma ; Genes, Retinoblastoma

OBJECTIVE(1) To investigate the promoter methylation status of gene p16(INK4a) and gene RB in breast carcinoma and the adjacent non-neoplastic hyperplastic epithelial tissue. (2) To study the correlation of p16(INK4a) gene expression at protein level with the abnormal gene methylation, the clinical manifestation and the pathological parameters.

METHODSMethylation status of promoters of p16(INK4a) gene and RB gene was detected by using methylation specific PCR in 46 cases of breast cancer, 22 cases of the adjacent non-neoplastic hyperplastic epithelium tissue and 7 cases of normal breast tissue. In addition, the p16(INK4a) gene protein expression level was also detected using immunohistochemical technique(SP method) in 46 cases of breast cancer and 22 cases of the adjacent hyperplastic epithelial tissue.

RESULTSThe methylation rate of p16(INK4a) gene was 23.9% (11/46) in breast cancer, 18.2% (4/22) in the adjacent non-neoplastic hyperplastic epithelial tissue and 1/7 in normal breast tissue, respectively. The methylation rate of RB gene was relatively low, which was 10.8% (5/46), 9.1% (2/22) and 0(0/7) in the above 3 groups, respectively. Methylation rate of p16(INK4a) gene and RB gene was not significantly different among the breast cancer, the adjacent non-neoplastic hyperplastic tissue and the normal tissues (P > 0.05). However, the methylation status of p16(INK4a) gene was closely correlated with its protein expression level and the negative ER expression result of the breast cancer (P < 0.05), but not correlated with the size of the cancer, differentiation status, lymph node metastasis, and age. The methylation status of RB gene was correlated with lymph node metastasis, but not with the size, the differentiation status, ER expression of the breast cancer and the age of the patients.

CONCLUSIONSThe abnormal methylation of p16(INK4a) gene may not play a significant role in the early stage of breast cancinogenesis, but may play a role of in the progression of the cancer. RB gene methylation may also be a indicator in choice to identify the progression and prognosis of breast cancer.

Adult ; Aged ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; genetics ; metabolism ; pathology ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; Female ; Gene Expression Regulation, Neoplastic ; Genes, p16 ; Humans ; Lymphatic Metastasis ; Middle Aged ; Receptors, Estrogen ; metabolism ; Retinoblastoma Protein ; genetics ; metabolism

PURPOSE: The aim of this study was to determine the expressions of Rb, p16, and cyclin D1 in soft tissue sarcomas, and we also wanted to identify the prognostic factors according to the clinicalpathologic features. MATERIALS AND METHODS: We reviewed the charts and radiographic films of 66 sarcoma patients. Tissue samples were collected from these patients. Immunochemistry was performed using formalin-fixed, paraffin-embedded tissue samples to examine the expressions of p16, Rb, and cyclin D1 proteins. RESULTS: The median duration of overall survival was 47.8 months (range, 20.0 to 70.7 months) and the 5 years survival rate was 39%. As for the correlation between the degree of immunohistochemical staining for Rb protein and the histological tumor grades, there was a significant difference with a p-value of 0.019. However, no significant correlation was shown for p16 and cyclin D1. The overall survival duration of the Rb negative group (staining cell <20%) and the heterogeneous group (cell staining 20 to 80%) was 53.5+/-6.6 months and the overall survival duration of the Rb homogeneous group was 18.3+/-6.4 months, and there was a significant difference with a p-value of 0.016. However, no significant difference was shown between the survival rate according to the p16 and cyclin D1 expressions. On the multivariate analysis that was done with Rb, p16, the tumor size, grade and site, and patient age, the Rb gene expression was the most significant independent prognostic factor with a risk ratio of 3.01 (p=0.04). CONCLUSION: The expression of Rb protein was correlated with the histologic grade and overall survival of patients with soft tissue sarcomas.
Cyclin D1 ; Cyclins ; Genes, Retinoblastoma ; Humans ; Immunochemistry ; Multivariate Analysis ; Odds Ratio ; Proteins ; Retinoblastoma Protein ; Sarcoma ; Survival Rate ; X-Ray Film

OBJECTIVE: p16 is cyclin-dependent kinase (CDK) inhibitor which decelerates cell cycle by inactivating CDKs that phosphorylate retinoblastoma protein (pRb). In cervical carcinogenesis, abnormality of p16 gene such as methylation of p16 gene promoter was investigated as an important factor. The aims of our study are to investigate the expression of p16 gene, methylation of p16 gene promoter region, and HPV typing in uterine cervical neoplasia. METHODS: A total of 104 samples (CIN1, 30 CIN2,3 45, invasive cancer, 29) were included. Expression of p16 was analyzed by immunohistochemistry, methylation of p16 gene promoter region was analyzed with methylation specific polymerase chain reaction (MSP) and we examed the result of HPV DNA testing. RESULTS: 1. In high risk HPV and low risk or negative group, p16 gene expression was observed in CIN1 (30% vs 23%), CIN2, 3 (64% vs 58%) and in invasive cancer (80% vs 37%) respectively. In invasive cancer, p16 gene expression of high risk HPV group was statistically higher than that of low risk or negative group. 2. In high risk HPV and low risk or negative group, p16 promoter methylation was observed in CIN1 (23% vs 17%), CIN2, 3 (25% vs 47%) and in invasive cancer (19% vs 87%) respectively. In invasive cancer, p16 promoter methylation of low risk or negative HPV group was statistically higher than that of low risk or negative group. CONCLUSION: p16 gene expression would be marker for CIN and cancer. Methylation of p16 promoter region may be one of the important mechanism for uterine cervical carcinogenesis especially in negative or low risk HPV group. but further studies are needed to reinforce this statement.
Carcinogenesis ; Cell Cycle ; DNA Methylation ; Genes, p16* ; Human Papillomavirus DNA Tests ; Immunohistochemistry ; Methylation* ; Phosphotransferases ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; Retinoblastoma Protein ; Uterine Cervical Neoplasms

PURPOSE: Breast cancer is one of the most frequent malignant tumors in Korea. The major tumor suppressor genes (TSGs) such as p16, Rb, E-cadherin and p53 may play important roles in cell cycle regulation, apoptosis and the regulation of the expression of other genes as well as tumor suppression. Microsatellite alteration such as loss of heterozygosity (LOH) have been reported to be a novel mechanism of carcinogenesis and a useful prognostic factor for many malignant tumors. Also, LOH is also known to be related with allelic loss of various TSGs. This study evaluated LOH of 4 TSGs in invasive ductal carcinomas (IDCs) and we correlated these results with the clinicopathological factors. METHODS: LOH analysis was carried out using a polymerase chain reaction with 12 polymorphic microsatellite markers of 4 TSGs in 50 surgically resected tumors and their non-tumorous counterparts. RESULTS: There was no detectable LOH in the normal tissue. LOH was detected in 86% of the 50 cases of IDCs. LOH was detected on all chromosomes and this showed a statistical difference between benign tumor and malignant tumor. LOH of p16, Rb, E-cadherin and p53 TSGs was detected in 36%, 26%, 54% and 60% of the tumors, respectively. LOH of the p16 and Rb genes was inversely correlated with tumor grade 1. The low rate of detecting LOH on the E-cadherin gene was noted in T1 tumor and stage I disease. LOH of the p53 gene correlated well with the tumor size and stage. The LOH-High results correlate well with the tumor size and stage and the LOH-High results are similar to those of the p53 gene LOH. CONCLUSION: These results suggest that LOH of the 4 major TSGs may contribute to the development and invasion of IDCs. Also, the combined use of various LOH markers may help in deciding the prognosis of IDCs.
Apoptosis ; Breast Neoplasms ; Cadherins ; Carcinogenesis ; Carcinoma, Ductal* ; Cell Cycle ; Genes, p53 ; Genes, Retinoblastoma ; Genes, Tumor Suppressor* ; Korea ; Loss of Heterozygosity* ; Microsatellite Repeats ; Polymerase Chain Reaction ; Prognosis

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

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

OBJECTIVETo detect the loss of heterozygosity (LOH) in esophageal squamous cell carcinoma and adjacent high-grade squamous dysplasia, and to evaluate possible tumor suppressor genes in the development and progression of invasive malignancy.

METHODSLOH was detected in normal esophageal mucosa, high grade squamous dysplasia and esophageal squamous cell carcinoma using microdissection and polymerase chain reaction technology. The changes of LOH at seven microsatellite markers and the relationship between LOH rate and clinicopathologic parameters were analyzed.

RESULTSIn high grade squamous dysplasia, LOH was detected at D13S802 (40%), D13S267 (32%), D13S221 (31%), D9S942 (30%), D17S520 (24%) and D9S171 (33%). However, D17S1798 LOH was not detected. In invasive squamous cell carcinoma, LOH was detected as follows: D13S267 (71%), D13S802 (58%), D17S520 (55%), D13S221 (45%), D9S942 (43%), D9S171 (33%) and D17S1798 (11%). The frequency of LOH in the seven microsatellite markers, the pathologic grade, clinical stage and occurrence of lymph node metastasis did not show any statistically significant correlation (P > 0.05).

CONCLUSIONSThe progression from normal squamous epithelium to high grade squamous dysplasia and subsequently to invasive squamous cell carcinoma of the esophagus was associated with accumulation of genetic errors. Possible tumor suppressor genes related to the development of esophageal squamous cell carcinoma may exist near D13S802 (13q12.12). Possible tumor suppressor genes near D13S267 (13q13.1), D17S1798 (17p13.3) and D17S520 (17p13.1) may be related to the progression of esophageal squamous cell carcinoma.

Adult ; Aged ; Carcinoma, Squamous Cell ; genetics ; Chromosome Mapping ; Chromosomes, Human, Pair 13 ; Chromosomes, Human, Pair 17 ; Chromosomes, Human, Pair 9 ; Esophageal Neoplasms ; genetics ; Female ; Genes, Retinoblastoma ; Genes, Tumor Suppressor ; Genes, p16 ; Genes, p53 ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged ; Precancerous Conditions ; genetics