MyMedR

Displaying all 4 publications

Abstract:

Sort:

Tissue microarray immunohistochemical profiles of p53 and pRB in hepatocellular carcinoma and hepatoblastoma

Azlin AH, Looi LM, Cheah PL

Asian Pac J Cancer Prev, 2014;15(9):3959-63.
PMID: 24935581

The tumour suppressor genes, p53 and pRb, are known to play important roles in neoplastic transformation. While molecular routes to the uncontrolled growth of hepatocytes, leading to primary liver cancer have generated considerable interest, the roles of p53 and pRb mutations in hepatocellular carcinoma (HCC) and hepatoblastoma (HB) remain to be clarified. We examined the immunohistochemical expression of p53 and pRb gene products in 26 HCC and 9 HB, sampled into tissue microarray blocks. 10 (38%) of 26 HCC showed > 10% tumour nuclear staining for p53 protein, 3 of these also being HbsAg positive. Conversely, none of 9 HB expressed nuclear p53 immunopositivity. Some 24 (92%) HCC and 8 (89%) HB showed loss of pRb nuclear expression. Two of the 26 HCC and one of the 9 HB showed >10% tumour nuclear staining for pRb protein. Our results suggest that p53 does not have an important role in the development of HB but may contribute in HCC. There is also loss of pRb expression in the majority of HCC and HB, supporting loss of pRb gene function in the hepatocarcinogenesis pathway. However, a comparison of the staining profiles of p53 and pRb proteins in HCC and HB did not reveal a consistent pattern to differentiate between the two types of tumours immunohistochemically. Hence the use of p53 and pRB protein expression has no contribution in the situation where there is a diagnostic difficulty in deciding between HCC and HB.

Matched MeSH terms: Retinoblastoma Protein/genetics*
Spectrum of germ-line RB1 gene mutations in Malaysian patients with retinoblastoma

Mohd Khalid MK, Yakob Y, Md Yasin R, Wee Teik K, Siew CG, Rahmat J, et al.

Mol Vis, 2015;21:1185-90.
PMID: 26539030

The availability of molecular genetic testing for retinoblastoma (RB) in Malaysia has enabled patients with a heritable predisposition to the disease to be identified, which thus improves the clinical management of these patients and their families. In this paper, we presented our strategy for performing molecular genetic testing of the RB1 gene and the findings from our first 2 years of starting this service.

Matched MeSH terms: Retinoblastoma Protein/genetics*
Expression of retinoblastoma protein and P16 proteins in classic Hodgkin lymphoma: relationship with expression of p53 and presence of Epstein-Barr virus in the regulation of cell growth and death

Kim LH, Peh SC, Poppema S

Hum Pathol, 2006 Jan;37(1):92-100.
PMID: 16360421

Deregulation of several genes involved in cell cycle control has been reported in classic Hodgkin lymphoma (cHL). This study aimed to investigate the expression of tumor suppressor proteins (P16(INK4A), retinoblastoma protein, and p53) in cHL in relation to the proliferation and apoptosis of Hodgkin/Reed-Sternberg (H/RS) cells, correlating with the status of Epstein-Barr virus (EBV). A total of 66 cHL cases and 10 nonneoplastic reactive lymphoid tissues were retrieved from the archives. Immunohistochemistry technique was used for the detection of protein expression. Presence of EBV infection was detected by EBV early RNA in situ hybridization. p16(INK4A) gene deletion status was assessed by fluorescence in situ hybridization technique. Expression of P16(INK4A) was observed in 49.2% of the cases, whereas positive retinoblastoma protein and p53 expressions in the H/RS cells were detected in 89.1% and 81.5% of the cases, respectively. Epstein-Barr virus positivity was detected in 53.0% of the cases. Proliferation marker, Ki-67 expression, was observed in 86.7% of the cases. There was no significant correlation between the expression of the various tumor suppressor proteins and Ki-67. Retinoblastoma protein and p53 were also not associated with the presence of EBV. An inverse relationship was observed between the expression of P16(INK4A) and the presence of EBV. There were no significant homozygous or hemizygous deletions of the p16(INK4A) gene. However, an aberrant copy number of chromosome 9 with the loss of one or more p16(INK4A) loci was detected in all cases assessable by fluorescence in situ hybridization. Loss of function of one or more tumor suppressor proteins may be involved in defective cell regulation of H/RS cells. Epstein-Barr virus may have a role in inhibiting P16(INK4A) expression, thus resulting in a perturbed p16(INK4A)-Rb cell cycle checkpoint.

Matched MeSH terms: Retinoblastoma Protein/genetics
Gamma-tocotrienol modulation of senescence-associated gene expression prevents cellular aging in human diploid fibroblasts

Makpol S, Zainuddin A, Chua KH, Yusof YA, Ngah WZ

Clinics (Sao Paulo), 2012;67(2):135-43.
PMID: 22358238

OBJECTIVE: Human diploid fibroblasts undergo a limited number of cellular divisions in culture and progressively reach a state of irreversible growth arrest, a process termed cellular aging. The beneficial effects of vitamin E in aging have been established, but studies to determine the mechanisms of these effects are ongoing. This study determined the molecular mechanism of γ-tocotrienol, a vitamin E homolog, in the prevention of cellular aging in human diploid fibroblasts using the expression of senescence-associated genes.
METHODS: Primary cultures of young, pre-senescent, and senescent fibroblast cells were incubated with γ-tocotrienol for 24 h. The expression levels of ELN, COL1A1, MMP1, CCND1, RB1, and IL6 genes were determined using the quantitative real-time polymerase chain reaction. Cell cycle profiles were determined using a FACSCalibur Flow Cytometer.
RESULTS: The cell cycle was arrested in the G(0)/G(1) phase, and the percentage of cells in S phase decreased with senescence. CCND1, RB1, MMP1, and IL6 were upregulated in senescent fibroblasts. A similar upregulation was not observed in young cells. Incubation with γ-tocotrienol decreased CCND1 and RB1 expression in senescent fibroblasts, decreased cell populations in the G(0)/G(1) phase and increased cell populations in the G(2)/M phase. γ-Tocotrienol treatment also upregulated ELN and COL1A1 and downregulated MMP1 and IL6 expression in young and senescent fibroblasts.
CONCLUSION: γ-Tocotrienol prevented cellular aging in human diploid fibroblasts, which was indicated by the modulation of the cell cycle profile and senescence-associated gene expression.

Matched MeSH terms: Retinoblastoma Protein/genetics