An immunohistochemical study of p21 and p53 expression in primary node-positive breast carcinoma

Gamma irradiation and targeted radionuclides enhance the expression of the noradrenaline transporter transgene controlled by the radio-inducible p21(WAF1/CIP1) promoter

The use of radiation-inducible promoters to drive transgene expression offers the possibility of temporal and spatial regulation of gene activation. This study assessed the potential of one such promoter element, p21(WAF1/CIP1) (WAF1), to drive expression of the noradrenaline transporter (NAT) gene, which conveys sensitivity to radioiodinated meta-iodobenzylguanidine (MIBG). An expression vector containing NAT under the control of the radiation-inducible WAF1 promoter (pWAF/NAT) was produced. The non-NAT expressing cell lines UVW (glioma) and HCT116 (colorectal cancer) were transfected with this construct to assess radiation-controlled WAF1 activation of the NAT gene. Transfection of UVW and HCT cells with pWAF/NAT conferred upon them the ability to accumulate [(131)I]MIBG, which led to increased sensitivity to the radiopharmaceutical. Pretreatment of transfected cells with γ radiation or the radiopharmaceuticals [(123)I]MIBG or [(131)I]MIBG induced dose- and time-dependent increases in subsequent [(131)I]MIBG uptake and led to enhanced efficacy of [(131)I]MIBG-mediated cell kill. Gene therapy using WAF1-driven expression of NAT has the potential to expand the use of this therapeutic modality to tumors that lack a radio-targetable feature.

Overexpressions of Cyclin B1, cdc2, p16 and p53 in human breast cancer: the clinicopathologic correlations and prognostic implications

PURPOSE

The molecular mechanisms that are responsible for the initiation and progression of breast cancers are largely unknown. This study was to analyze the cyclin B1, cdc2, p53 and p16 tumor suppressor genes in human breast cancer.

MATERIALS AND METHODS

To investigate the role of cyclin B1, cdc2, p53 and p16 in the pathogenesis and progression of breast carcinomas, 98 cases of breast cancers were examined by immunohistochemical method. The correlations of cyclin B1, cdc2, p53 and p16 expression with various clinico-pathologic findings were analysed.

RESULTS

In the normal breast tissues, cyclin B1, cdc2 and p16 were weakly expressed, while p53 was not expressed. On the other hand, cyclin B1, cdc2, p53 and p16 were overexpressed in breast cancer, showing correlation between the expression of cyclin B1 and cdc2 and breast cancers (p=0.00). The overexpressions of cdc2 and p16 were correlated with an infiltrative tumor border pattern and this was statistically significant (p<0.05). In addition, the overexpression of cdc2 was correlated with histologic high grade carcinomas (p=0.00).

CONCLUSION

Cyclin B1 and cdc2 appeared to be involved in the genesis or progression of breast cancers. In addition, the overexpressions of p16 and p53 may play important roles in more aggressive tumor and the overexpression of cdc2 is associated with progression of tumor to a higher grade of breast carcinomas. The deranged overexpressions of cyclin B1, cdc2, p16 and p53 may play an important role in human breast carcinogenesis.

Growth factor receptors and apoptosis regulators: signaling pathways, prognosis, chemosensitivity and treatment outcomes of breast cancer

Biomarkers of breast cancer are necessary for prognosis and prediction to chemotherapy. Prognostic biomarkers provide information regarding outcome irrespective of therapy, while predictive biomarkers provide information regarding response to therapy. Candidate prognostic biomarkers for breast cancers are growth factor receptors, steroid receptors, Ki-67, cyclins, urokinase plasminogen activator, p53, p21, pro- and anti-apoptotic factors, BRCA1 and BRCA2. But currently, the predictive markers are Estrogen and Progesterone receptors responding to endocrine therapy, and HER-2 responding to herceptin. But there are numerous breast cancer cases, where tamoxifen is ineffective even after estrogen receptor positivity. This lead to search of new prognostic and predictive markers and the number of potential markers is constantly increasing due to proteomics and genomics studies. However, most biomarkers individually have poor sensitivity or specificity, or other clinical value. It can be resolved by studying various biomarkers simultaneously, which will help in better prognosis and increasing sensitivity for chemotherapeutic agents. This review is focusing on growth factor receptors, apoptosis markers, signaling cascades, and their correlation with other associated biomarkers in breast cancers. As our knowledge regarding molecular biomarkers for breast cancer increases, prognostic indices will be developed that combine the predictive power of individual molecular biomarkers with specific clinical and pathologic factors. Rigorous comparison of these existing as well as emerging markers with current treatment selection is likely to see an escalation in an era of personalized medicines to ensure the breast cancer patients receive optimal treatment. This will also solve the treatment modalities and complications related to chemotherapeutic regimens.

Cell cycle machinery: links with genesis and treatment of breast cancer

Loss of normal growth control is a hallmark of cancer. Thus, understanding the mechanisms of tissue-specific, normal growth regulation and the changes that occur during tumorigenesis may provide insights of both diagnostic and therapeutic importance. Control of cell proliferation in the normal mammary gland is steroid hormone (estrogen and progestin)-dependent, involves complex interactions with other hormones, growth factors and cytokines and ultimately converges on activation of three proto-oncogenes (c-Myc, cyclin D1 and cyclin E1) that are rate limiting for the G1 to S phase transition during normal cell cycle progression. Mammary epithelial cell-specific overexpression of these genes induces mammary carcinoma in mice, while cyclin D1 null mice have arrested mammary gland development and are resistant to carcinoma induced by the neu/erbB2 and ras oncogenes. Furthermore, c-Myc, cyclins D1, E1 and E2 are commonly overexpressed in primary breast cancer where elevated expression is often associated with a more aggressive disease phenotype and an adverse patient outcome. This may be due in part to overexpression of these genes conferring resistance to endocrine therapies since in vitro studies provide compelling evidence that overexpression of c-Myc and to a lesser extent cyclin D1 and cyclin E1, attenuate the growth inhibitory effects of SERMS, antiestrogens and progestins in breast cancer cells. Thus, abnormal regulation of the expression of cell cycle molecules, involved in the steroidal control of cell proliferation in the mammary gland, are likely to be directly involved in the development, progression and therapeutic responsiveness of breast cancer. Furthermore, a more detailed understanding of these pathways may identify new targets for therapeutic intervention particularly in endocrine-unresponsive and endocrine-resistant disease.

Expression of p21WAF in salivary gland mucoepidermoid carcinoma and its relation to histologic grade

The biologic behavior and factors influencing the development of salivary gland mucoepidermoid carcinoma are not fully understood. Alteration of the cyclin-dependant kinase inhibitor p21(WAF) could cause uncontrolled proliferation leading to cancer. Thirty-five mucoepidermoid carcinomas were graded and immunohistochemically stained for p21(WAF). The percentage of positive tumor cells was determined using an eyepiece graticule and a computer-assisted image analyzer, which revealed 8.6% and 22.9% of the cases to be positive for p21(WAF), respectively. A statistically significant correlation was not observed between p21(WAF) and grading. Considering the absence of p21(WAF) expression in most mucoepidermoid carcinomas, it appears that the inhibitory effect of p21(WAF) on cell growth is removed in most cases. Given the lack of correlation with tumor grade, it is possible that the impact of p21(WAF) is in the earlier stages of tumorigenesis. A p53-independent pathway of p21(WAF) induction may exist for the small proportion of tumors that showed positivity.

Of humans and canines: Immunohistochemical analysis of PCNA, Bcl-2, p53, cytokeratin and ER in mammary tumours

Mammary tumours are the most common neoplasms in humans and canines. Human and canine mammary tumours share several important epidemiological, clinicopathological and biochemical features. Development of mammary tumours involves accumulation of mutant cells caused by excessive proliferation and insufficient apoptosis or dysregulation of cellular differentiation. The present study was therefore designed to investigate the expression of proliferation, differentiation, and apoptosis associated proteins together with expression of estrogen receptors (ER) in both human and canine mammary tumours. Thirty breast cancer patients categorized as pre- and postmenopausal, and 30 mammary gland tumours obtained from bitches were included in this study. The expression of proliferating cell nuclear antigen (PCNA), Bcl-2, p53, cytokeratin and ER in tumour tissues and adjacent tissues were investigated using immunohistochemical staining. While the expression of PCNA, Bcl-2, p53 and ER was significantly increased, expression of cytokeratin was significantly lower in both human as well as canine mammary tumours compared to corresponding adjacent tissues. The magnitude of the changes was however more pronounced in premenopausal patients compared to postmenopausal patients. The changes in proliferation, apoptosis and differentiation associated proteins in human and canine mammary tumours validate use of the canine model to understand the molecular mechanisms of mammary carcinogenesis.

Relationship between viral factors, axillary lymph node status and survival in breast cancer

PURPOSE

Our previous study based on the results of polymerase chain reaction and Southern hybridization for the detection of Human papilloma virus (HPV), Cytomegalovirus (CMV), Epstein-Barr virus (EBV), Herpes simplex virus (HSV)-1, HSV-2, and Human herpesvirus (HHV)-8 DNA in non-familial breast cancer patients suggest that the viruses associated with breast cancer are HHV-8 > EBV (P < 0.01). Therefore, efforts were made to further investigate the association between breast cancer with nodal status and viral infections.

METHODS

Sixty-two breast cancer patients and their mammary specimens were enrolled in this retrospective study. The presence of these six potential oncogenic viruses was analyzed to establish the relationship between nodal status and treatment outcome. Statistical analyses were used for the assessment of variables, including viral positivity and clinical feature.

RESULTS

Viral positivity was not significantly different comparing node-positive and node-negative patients (P > 0.05). When the viral factors were not entered for statistical analyses, no variable was significantly related to overall survival. However, tumor stage, tumor size, nodal status , and estrogen receptor were significantly related to relapse-free survival (P < 0.05). For viral factors, the number of infecting viruses is related to the overall and relapse-free survivals. Only when V0 or V(0, 1) was grouped for comparison with other multiply virus-infected subgroups, were the overall and relapse-free survivals significantly different (P < 0.005 or P < 0.001). The results suggest that HSV-1, HHV-8, EBV, CMV, and HPV were related to overall survival, however, only HHV-8 and CMV were related to relapse-free survival (P < 0.05 or P < 0.01).

CONCLUSION

Virus factor is significantly related to human breast cancer, not only in terms of the oncogenetic process, but also in overall and relapse-free survivals.

Murine mammary adenocarcinoma cells transfected with p53 and/or Flt3L induce antitumor immune responses

Transfection of tumors with tumor-associated antigens (Ags) or cytokines can increase immunogenicity and slow down tumor growth. However, the effect of cotransfection with genes that encode a tumor-associated Ag, such as the tumor suppressor gene p53, and a cytokine has been rarely investigated. We report that transfection of 4T1 mammary tumor cells (p53-null) with the dendritic cell (DC) growth factor, fms-like tyrosine kinase 3 ligand (Flt3L), significantly delayed their growth in vivo, resulting in the rejection of 100% of the tumors formed by injection of tumor cells cotransfected with Flt3L and p53. Immunization with irradiated 4T1 cells transfected with Flt3L induced DC infiltration of the immunization site and significantly increased the antitumor T-cell responses. Further, immunization with irradiated 4T1 cells cotransfected with p53 and Flt3L significantly increased p53-specific immune responses, as compared to vaccination with 4T1 cells transfected with either Flt3L or p53 alone. These responses included increased activity against clone 66 (Cl-66), a sister tumor to 4T1 with high murine mutant p53 expression levels. Challenge with Cl-66 revealed that immunization with irradiated 4T1-Flt3L-p53 cells significantly slowed growth, prolonged survival, and resulted in complete remissions. Further, immunization with irradiated 4T1-Flt3L also slowed Cl-66 growth, although to a lesser extent than 4T1-Flt3L-p53. We suggest that immunization with DCs transfected with the Flt3L transgene and a tumor Ag may potentially heighten T-cell responses and therapeutic activity.

Clinicopathological study of the expression of hsp27, pS2, cathepsin D and metallothionein in primary invasive breast cancer

Expression of the hormone-related proteins hsp27, pS2, and also of cathepsin D (CD) and metallothionein (MT) was studied by immunohistochemistry and analyzed against clinical data in breast cancer. Archived material of paraffin-embedded breast carcinoma tissues from a cohort of 134 patients with primary invasive breast cancer was used. Hsp27 and pS2 (>10% of tumor cells stained) were found to be expressed in 63.6% and 37.6% of cases, respectively, and were correlated negatively with grading (P=0.006 and 0.01) and positively with estrogen receptors (ER) (P=0.04 and 0.04). pS2 expression was correlated with lymph node status (P=0.02), tumor size (P=0.01), progesterone receptor (PR) content (P=0.02), hsp27 (P=0.015) and bcl-2 protein (P=0.001). An inverse relationship between pS2 expression and the expression of p53 protein (P=0.005) and proliferation-associated index MIB1 (P<0.0001) was noted. Stromal cathepsin D was positively correlated with tumor grade (P=0.01), PCNA (P=0.007), MIB1 (P=0.001) and p53 (P=0.01), and negatively with ER (P=0.04) and bcl-2 (P<0.0001). MT was correlated positively with stromal CD (P=0.007) and inversely with PgR (P=0.04). Univariate analysis showed CD expression to be a positive prognostic factor for survival (P=0.035), with borderline significance, while MT was more strongly positive (P=0.01). However, none of the proteins studied was found to be related to disease outcome in univariate analysis. Our data show that hsp27, pS2 and stromal CD expression may reflect tumor differentiation and the functional status of ER in breast cancer, but stromal CD and tumor MT expression were the only factors found that may be of limited prognostic value.

The clinicopathological significance of p53 and p21 expression in squamous cell carcinoma of hypopharyngeal cancer

To evaluate the roles of p53 and p21 expression in the squamous cell carcinoma of hypopharyngeal cancer, we performed the immunohistochemical studies in 58 patients with hypopharyngeal cancer. We found significant correlation between a high expression of p53 and a histological grade of well differentiation, advanced tumor (T) and TNM stage. Furthermore, low expression of p21 correlated significantly with advanced TNM stage and positive nodal status. Cox's regression analysis revealed tumor stage and nodal status were the only prognostic factors for survival. Therefore, we concluded that p53 and p21 are useful markers in predicting some clinicopathological features in hypopharyngeal cancer.

Transcriptional Targeting in Cancer Gene Therapy

Cancer gene therapy has been one of the most exciting areas of therapeutic research in the past decade. In this review, we discuss strategies to restrict transcription of transgenes to tumour cells. A range of promoters which are tissue-specific, tumour-specific, or inducible by exogenous agents are presented. Transcriptional targeting should prevent normal tissue toxicities associated with other cancer treatments, such as radiation and chemotherapy. In addition, the specificity of these strategies should provide improved targeting of metastatic tumours following systemic gene delivery. Rapid progress in the ability to specifically control transgenes will allow systemic gene delivery for cancer therapy to become a real possibility in the near future.