A prospective trial of midwest breast cancer patients: a p53 gene mutation is the most important predictor of adverse outcome

Prognostic significance of RNA-based TP53 pathway function among estrogen receptor positive and negative breast cancer cases

TP53 and estrogen receptor (ER) are essential in breast cancer development and progression, but TP53 status (by DNA sequencing or protein expression) has been inconsistently associated with survival. We evaluated whether RNA-based TP53 classifiers are related to survival. Participants included 3213 women in the Carolina Breast Cancer Study (CBCS) with invasive breast cancer (stages I-III). Tumors were classified for TP53 status (mutant-like/wildtype-like) using an RNA signature. We used Cox proportional hazards models to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer-specific survival (BCSS) among ER- and TP53-defined subtypes. RNA-based results were compared to DNA- and IHC-based TP53 classification, as well as Basal-like versus non-Basal-like subtype. Findings from the diverse (50% Black), population-based CBCS were compared to those from the largely white METABRIC study. RNA-based TP53 mutant-like was associated with BCSS among both ER-negatives and ER-positives (HR (95% CI) = 5.38 (1.84-15.78) and 4.66 (1.79-12.15), respectively). Associations were attenuated when using DNA- or IHC-based TP53 classification. In METABRIC, few ER-negative tumors were TP53-wildtype-like, but TP53 status was a strong predictor of BCSS among ER-positives. In both populations, the effect of TP53 mutant-like status was similar to that for Basal-like subtype. RNA-based measures of TP53 status are strongly associated with BCSS and may have value among ER-negative cancers where few prognostic markers have been robustly validated. Given the role of TP53 in chemotherapeutic response, RNA-based TP53 as a prognostic biomarker could address an unmet need in breast cancer.

Novel microtubule inhibitor SQ overcomes multidrug resistance in MCF-7/ADR cells by inhibiting BCRP function and mediating apoptosis

The occurrence of multidrug resistance (MDR) is one of the impediments in the clinical treatment of breast cancer, and MDR breast cancer has abnormally high breast cancer resistance protein (BCRP/ABCG2) expression. However, there are currently no clinical drugs that inhibit this target. Our previous study found that 2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ0814061/SQ), a small molecule drug with low toxicity to normal tissues, could target microtubules, inhibit the proliferation of breast cancer, and reduce its migration and invasion abilities. However, the effect and the underlying mechanism of SQ on MDR breast cancers are still unknown. Therefore, in this study, we investigated the effect of SQ on adriamycin-resistant MCF-7 (MCF-7/ADR) cells and explored the underlying mechanism. The MTT assay showed that SQ had potent cytotoxicity to MCF-7/ADR cells. In particular, the results of western blot and flow cytometry proved that SQ could effectively inhibit the expression of BCRP in MCF-7/ADR cells to decrease its drug delivery activity. In addition, SQ could block the cell cycle at G2/M phase in parental and MCF-7/ADR cells, thereby mediating cell apoptosis, which was related with the inhibition of PI3K-Akt-MDM2 pathway. Taken together, our findings indicate that SQ overcomes multidrug resistance in MCF-7/ADR cells by inhibiting BCRP function and mediating apoptosis through PI3K-Akt-MDM2 pathway inhibition.

Familial Breast Cancer: Disease Related Gene Mutations and Screening Strategies for Chinese Population

BACKGROUND

About 5%-10% of the breast cancer cases have a hereditary background, and this subset is referred to as familial breast cancer (FBC). In this review, we summarize the susceptibility genes and genetic syndromes associated with FBC and discuss the FBC screening and high-risk patient consulting strategies for the Chinese population.

METHODS

We searched the PubMed database for articles published between January 2000 and August 2021. Finally, 380 pieces of literature addressing the genes and genetic syndromes related to FBC were included and reviewed.

RESULTS

We identified 16 FBC-related genes and divided them into three types (high-, medium-, and low-penetrance) of genes according to their relative risk ratios. In addition, six genetic syndromes were found to be associated with FBC. We then summarized the currently available screening strategies for FBC and discussed those available for high-risk Chinese populations.

CONCLUSION

Multiple gene mutations and genetic disorders are closely related to FBC. The National Comprehensive Cancer Network (NCCN) guidelines recommend corresponding screening strategies for these genetic diseases. However, such guidelines for the Chinese population are still lacking. For screening high-risk groups in the Chinese population, genetic testing is recommended after genetic counseling.

TP53 mutations determined by targeted NGS in breast cancer: a case-control study

Background: Tumor protein 53 (TP53) gene mutations are identified in up to 37% of breast tumors especially in HER-2 positive and basal-like subtype. Previous studies have indicated TP53 mutations as a prognostic biomarker in breast cancer. However, most of these studies performed immunohistochemistry (IHC) for the detection of TP53 mutations.

Aim: The purpose of our study is to evaluate the role of TP53 somatic mutations detected via next-generation sequencing (NGS) as a potential prognostic marker in patients with breast cancer.

Materials and Methods: 82 female patients with Stage I–III breast cancer underwent NGS in paraffin blocks and blood samples during the period 25/09/2019 through 25/05/2021. 23 cases of somatic TP53 mutations and 23 cases of healthy controls were matched on age at diagnosis, menopausal status, histological subtype, histological grade, ki67 expression and disease stage.

Results: Mean age at diagnosis was 52.35 (SD; 11.47) years. The somatic TP53 mutation NM_000546.5:c.824G>A p.(Cys275Tyr) was most frequently detected. Co-existence of PIK3CA mutation was a common finding in somatic TP53-mutant tumors (4/23; 17.4%). Disease-free survival was shorter in TP53-mutated cases (16.3 months vs. 62.9 months). TP53 pathogenic somatic mutations were associated with a 8-fold risk of recurrence in the univariate Cox regression analysis (OR = 8.530, 95% CI: 1.81–40.117; p = 0.007).

Conclusions: Our case-control study suggests that TP53 somatic mutations detected by next-generation sequencing (NGS) are associated with an adverse prognosis in breast cancer.

TP53 Mutations and Outcomes in Breast Cancer: Reading beyond the Headlines

TP53 is the most frequently mutated gene in breast cancer, but its role in survival is confounded by different studies concluding that TP53 mutations are associated with negative, neutral, or positive outcomes. Closer examination showed that many studies were limited by factors such as imprecise methods to detect TP53 mutations and small cohorts that combined patients treated with drugs having very different mechanisms of action. When only studies of patients receiving the same treatment(s) were compared, they tended to agree. These analyses reveal a role for TP53 in response to different treatments as complex as its different biological activities. We discuss studies that have assessed the role of TP53 mutations in breast cancer treatment and limitations in interpreting reported results.

Prognostic Value of Mutations in TP53 and RAS Genes in Breast Cancer

The identification of molecular indicators of higher risk for specific subgroups of cancer patients may allow to develop more aggressive therapeutic strategies aimed at cases with the highest likelihood of response. This would avoid unnecessary toxicity to patients and alleviate the burden of cancer care for healthcare systems. Activated oncogenes and mutated tumor suppressor genes are causal determinants of the appearance and progression of tumors in man. They therefore represent potential indicators of prognosis and/or response to therapy. However, even in cases of well-studied oncogenes and tumor suppressor genes such as TP53 and RAS, their attributed prognostic and predictive value is often based on studies of insufficient statistical power that often lead to conflicting conclusions. Findings in favor or against the use of TP53 and RAS as prognostic and predictive indicators in breast cancer are reviewed and discussed here.

The effect of immunohistochemically detected p53 accumulation in prognosis of breast cancer; A retrospective survey of outcome

BACKGROUND

P53; a tumor suppressor gene has known to have a role in a group of human cancers. Its role in breast cancer; one of the most prevalent malignancies worldwide, is still controversial. The current study is designed to evaluate the prognostic role of p53 mutation in breast cancer.

METHODS

one hundred and eighty five breast cancer patients were studied in this retrospective study. P53 mutation was detected by accumulation of p53 protein in the patients' pathology samples. Immunohistochemistry (IHC) was used to detect the protein. The effect of p53 on the final outcome was assessed using Kaplan-Meier estimate of survival and compared by log-rank test. Prognostic effects analyzed by cox proportional hazard models.

RESULTS

while the stage of the disease at presentation was not significantly different between p53 positive and negative patients, those with p53 mutation had a significantly poorer outcome in terms of overall and disease-free survival rates (OS and DFS). In a multivariate analysis hazard ratio of p53 mutation was about 5 and 3.8 for OS and DFS respectively. They also had a higher cumulative incidence of relapse.

CONCLUSION

It seems that p53 mutation is an independent prognostic factor for breast cancer. Although larger prospective studies are needed to clarify the importance of such a conclusion.

Immunohistochemistry and scoring of Ki-67 proliferative index and p53 expression in gastric B cell lymphoma from Northern African population: a pilot study

BACKGROUND

This study aimed to clarify the Ki-67 distribution, p53 expression and their relationship with clinico-pathologic features of gastric B cell lymphoma from Northern African population.

METHODS

Twenty paraffin blocks of gastric lymphoma were retrieved from the archival materials of Department of Pathology, Central University Hospital of Sidi Bel Abbes (Western Algeria) from 2007 to 2013. Four µm section specimens were stained by immunohistochemical (IHC) technique with Ki-67 and p53 tumor markers. P values <0.05 were considered statistically significant.

RESULTS

Expression of p53 proteins and the mean proliferative index (PI) were compared between high grade gastric B cell lymphomas (DLBCL) and low grade gastric B cell lymphomas (gastric MALTs). p53 overexpression (P=0.007) and a high proliferation index Ki-67 (P=0.001) were significantly associated with gastric DLBCL. We found also a statistically significant correlation between p53 and Ki-67 (P=0.007) but no obvious relationships were found between Ki-67 PI and p53 expression as well as clinico-pathological features (age, sex, location, macroscopic type).

CONCLUSIONS

The IHC studies of Ki-67 and p53 expression in gastric B cell lymphoma can help in monitoring of patients at risk, and to give suitable treatment and management of patients.

A bioactive probe of the oxidative pentose phosphate cycle: novel strategy to reverse radioresistance in glucose deprived human colon cancer cells

The specific effects of glucose deprivation on oxidative pentose phosphate cycle (OPPC) function, thiol homeostasis, protein function and cell survival remain unclear due to lack of a glucose-sensitive chemical probe. Using p53 wild type and mutant human colon cells, we determined the effects of hydroxyethyl disulfide (HEDS) on NADPH, GSH, GSSG, total glutathione, total non-protein and protein thiol levels, the function of the DNA repair protein Ku, and the susceptibility to radiation-induced free radicals under normal glucose or glucose-deprived conditions. HEDS is rapidly detoxified in normal glucose but triggered a p53-independent metabolic stress in glucose depleted state that caused loss of NADPH, protein and non-protein thiol homeostasis and Ku function, and enhanced sensitivity of both p53 wild type and mutant cells to radiation induced oxidative stress. Additionally, high concentration of HEDS alone induced cell death in p53 wild type cells without significant effect on p53 mutant cells. HEDS offers a useful tool to gain insights into how glucose metabolism affects OPPC dependent stress-induced cellular functions and injury, including in tumor cells, where our findings imply a novel therapeutic approach to target glucose deprived tumor. Our work introduces a novel probe to address cancer metabolism and ischemic pathology.

Zeranol down-regulates p53 expression in primary cultured human breast cancer epithelial cells through epigenetic modification

Epidemiological studies have suggested that there are many risk factors associated with breast cancer. Silencing tumor suppressor genes through epigenetic alterations play critical roles in breast cancer initiation, promotion and progression. As a growth promoter, Zeranol (Z) has been approved by the FDA and is widely used to enhance the growth of beef cattle in the United States. However, the safety of Z use as a growth promoter is still under debate. In order to provide more evidence to clarify this critical health issue, the current study investigated the effect of Z on the proliferation of primary cultured human normal and cancerous breast epithelial cells (PCHNBECs and PCHBCECs, respectively) isolated from the same patient using MTS assay, RT-PCR and Western blot analysis. We also conducted an investigation regarding the mechanisms that might be involved. Our results show that Z is more potent to stimulate PCHBCEC growth than PCHNBEC growth. The stimulatory effects of Z on PCHBCECs and PCHBCECs may be mediated by its down-regulating expression of the tumor suppressor gene p53 at the mRNA and protein levels. Further investigation showed that the expression of DNA methylatransferase 1 mRNA and protein levels is up-regulated by treatment with Z in PCHBCECs as compared to PCHNBECs, which suggests a role of Z in epigenetic modification involved in the regulation of p53 gene expression in PCHBCECs. Our experimental results imply the potentially adverse health effect of Z in breast cancer development. Further study is continuing in our laboratory.

Glucose deprivation increases nuclear DNA repair protein Ku and resistance to radiation induced oxidative stress in human cancer cells

Recent studies have indicated that nutrient deprivation particularly glucose may play a major role in tumor cell tolerance to a generally oxidative stress environment in solid tumors. Here, we studied the impact of glucose deprivation on the response of human colon (HT29) and prostate (DU145) cancer cells to gamma radiation. A significant decrease in intracellular glucose level was observed in glucose deprived cells as measured by bioreductive assay. The survival of HT29 and DU145 were increased by 30 and 100% respectively when these cells were exposed to gamma radiation in the absence of glucose compared to that in the presence of glucose. In glucose depleted medium, glutathione (GSH), a free radical scavenger, content remained the same, and showed no correlation with the radiation resistance induced by glucose deprivation. Glucose regulated protein78 (GRP78), a stress response survival protein, was not significantly increased in cells deprived of glucose for 4 h compared to those cells in glucose. DNA repair protein Ku, which is known to play a major role in cellular resistance to radiation, was significantly increased in glucose deprived cancer cells that showed enhanced radiation resistance. These results have demonstrated, for the first time, that glucose deprivation mediated stress increased the expression of nuclear Ku and resistance to radiation induced oxidative stress in human cancer cells. The additional resistance caused by glucose deprivation in cancer cells has clinical significance since solid tumors are known to have low level of glucose due to diffusion limited blood supply and higher metabolic activity.

TP53 Mutations in Breast Cancer: Association with Ductal Histology and Early Relapse of Disease

Purpose

This study aimed to investigate the incidence of core domain TP53 mutations in Serbian breast cancer patients in view of their possible correlation with prognostic parameters, tumor characteristics and clinical disease course.

Methods

145 breast cancer patients were included. Data on clinical disease course were available for 100 patients including 30 node-negative and 70 node-positive patients. After surgery, node-positive patients underwent adjuvant chemotherapy, mostly CMF. TP53 mutations were detected by PCR-SSCP.

Results

31 mutations were found in 27/145 patients including 4/59 node-negative patients and 23/83 node-positive patients (4 double mutations). 26/31 TP53 mutations were found in patients with invasive ductal carcinoma and only 2 in patients with invasive lobular carcinoma. The presence of TP53 mutations was correlated with clinical disease course in premenopausal node-positive patients (n=70). 11/20 patients with TP53 mutations relapsed. Within the first 24 months of follow-up, significantly shorter disease-free intervals were observed in TP5. 3-mutated patients.

Conclusions

TP53 mutations correlated only with nodal status and ductal histology. The significance of the predominant distribution of TP53 mutations in tumors with a ductal histology for the aggressive behavior of these tumors has yet to be proved, since the favorable biological features of tumors with a lobular histology do not result in a better prognosis. Early relapse in mutated- TP5. 3 carriers may support data on its predictive value with respect to adjuvant CMF.

Detection of ultrarare somatic mutation in the human TP53 gene by bidirectional pyrophosphorolysis-activated polymerization allele-specific amplification

The detection of ultra-rare mutation in the presence of excess amounts of normal genomic DNA is highly advantageous in a number of circumstances, including: 1) identification of minimal residual disease for improved cancer chemotherapy; 2) measurement of mutation load to assess environmental mutagen exposure or endogenous DNA repair; and 3) prenatal diagnosis of paternally-derived mutations within fetal cells in the maternal circulation. Bidirectional pyrophosphorolysis activated polymerization allele-specific amplification (Bi-PAP-A) utilizes two opposing 3'-terminal blocked oligonucleotides (P(*)s) with 1 nucleotide overlap at their 3' termini. The selectivity of Bi-PAP-A derives from the serial coupling of pyrophosphorolysis and DNA polymerization. A total of 13 Bi-PAP-A assays were developed and validated for the human p53 gene (TP53). The sensitivity and specificity of each assay were determined with mutated and wild-type DNA templates, respectively. Bi-PAP-A has a sensitivity of one molecule for most assays and a selectivity (sensitivity:specificity) greater than 1:10(7)-1:10(9) for four of all six mutation types. Four assays with high selectivity were used to detect rare somatic mutations in blood white cells. The silent g.13147C>G (p.R156) mutation was present at an estimated frequency of 1.1 x 10(-7). The g.14523A>T (p.E285V), g.14487G>C (p.R273P), and g.14060G>C (p.G245R) mutations were undetectable with frequencies less than 2.0 x 10(-8). We conclude that Bi-PAP-A is a general and rapid method for detecting ultra-rare mutations.

Evaluation of the combined effect of p53 codon 72 polymorphism and hotspot mutations in response to anticancer drugs

Mutations in p53 are common events during carcinogenesis and have been suggested to affect sensitivity to chemotherapy. Recently, the common polymorphism at codon 72, resulting in either an arginine (72R) or proline (72P) residue, was shown to differentially affect the response to anticancer drugs. Here, we have generated isogenic lung cancer cell lines to evaluate the effect of six p53 hotspot mutations (R175H, G245S, R248W, R249S, R273H, and R282W) in conjunction with the codon 72 polymorphism, for their response to a variety of anticancer drugs, either alone or in combination. The data indicate that 72R mutations do not confer general resistance to cisplatin, etoposide, gemcitabine, vinblastine, and taxol. For doxorubicin, cells expressing 249-72R were more resistant than the 249-72P cells. Combined treatment with cisplatin + etoposide resulted in an additive effect in cells expressing most 72R and 72P mutations, except for the 175-72R cells which were refractory to combined treatment. However, combined treatment with cisplatin + gemcitabine resulted in the absence of an additive effect in cells expressing the 273-72R and 282-72R mutants, unlike their 72P counterparts. Nonetheless, all p53 mutants (72R or 72P) equally inhibited p73-mediated transcriptional activity in lung cancer cells, suggesting that the selective resistance conferred by some 72R mutants to certain drugs is probably due to other p73-independent effects of these mutants. Together, the data show that the status of codon 72 polymorphism and p53 mutations can be used as a means for prediction of treatment response, although variables for each cancer type requires detailed evaluation.

Proteomic identification of heat shock protein 90 as a candidate target for p53 mutation reactivation by PRIMA-1 in breast cancer cells

Introduction

A loss of p53 function resulting from mutation is prevalent in human cancers. Thus, restoration of p53 function to mutant p53 using small compounds has been extensively studied for cancer therapy. We previously reported that PRIMA-1 (for 'p53 reactivation and induction of massive apoptosis') restored the transcriptional activity of p53 target genes in breast cancer cells with a p53 mutation. By using functional proteomics approach, we sought to identify molecular targets that are involved in the restoration of normal function to mutant p53.

Methods

PRIMA-1 treated cell lysates were subjected to immunoprecipitation with DO-1 primary antibody against p53 protein, and proteins bound to p53 were separated on a denaturing gel. Bands expressed differentially between control and PRIMA-1-treated cells were then identified by matrix-assisted laser desorption ionization-time-of-flight spectrometry. Protein expression in whole cell lysates and nuclear extracts were confirmed by Western blotting. The effect of combined treatment of PRIMA-1 and adriamycin in breast cancer cells was determined with a cytotoxicity assay in vitro.

Results

PRIMA-1 treated cells distinctly expressed a protein band of 90 kDa that was identified as heat shock protein 90 (Hsp90) by the analysis of the 90 kDa band tryptic digest. Immunoblotting with isoform-specific antibodies against Hsp90 identified this band as the α isoform of Hsp90 (Hsp90α). Co-immunoprecipitation with anti-Hsp90α antibody followed by immunoblotting with DO-1 confirmed that p53 and Hsp90α were interacting proteins. PRIMA-1 treatment also resulted in the translocation of Hsp90α to the nucleus by 8 hours. Treatment of cells with PRIMA-1 alone or in combination with adriamycin, a DNA-targeted agent, resulted in increased sensitivity of tumor cells.

Conclusion

The studies demonstrate that PRIMA-1 restores the p53-Hsp90α interaction, enhances the translocation of the p53-Hsp90α complex and reactivates p53 transcriptional activity. Our preliminary evidence also suggests that PRIMA-1 could be considered in combination therapy with DNA-targeted agents for the treatment of breast cancer, especially for tumors with aberrant p53 function.

Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF

BACKGROUND

TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial.

PATIENTS AND METHODS

We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months).

RESULTS

TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF.

CONCLUSIONS

TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.

Mutational spectrum of p53 mutations in primary breast and ovarian tumors

Breast and ovarian cancers, like other cancers, occur due to genetic damage. Research aimed to determine the specific genes involved in the development of breast and ovarian cancers will help to understand how normal breast and ovarian epithelial cells escape regulation of proliferation, apoptosis and senescence. It was determined that approximately 10% of ovarian cancers and 20-30% of breast cancers arise in women who have inherited mutations in cancer susceptibility genes such as BRCA1, BRCA2 and other DNA repair genes. The ability to perform genetic testing permits the identification of women at increased risk who can then be offered preventive strategies. The vast majority of ovarian and breast cancers are sporadic, presumably resulting from the accumulation of genetic damage over lifetime. Several genes involved in breast and ovarian carcinogenesis have been identified, most notably the p53 tumor suppressor. The recent availability of expression microarrays has facilitated the simultaneous screening of thousands of genes and this will extend further the understanding of molecular events involved in the dynamic development of ovarian and breast cancers. Then, all this knowledge could be translated into effective screening, surveillance, prevention, and treatment strategies in the future.

Preoperative Chemotherapy and Endocrine Therapy in Patients with Breast Cancer

This review focuses on the aims, results, advantages, and possible disadvantages of preoperative chemotherapy and endocrine therapy. We present the recent improvements in terms of pathologic response rates that have resulted from new combinations of drugs. The change of established prognostic factors during neoadjuvant treatment, the need for new markers, and the consequences in terms of clinical decision-making are demonstrated. We discuss the risk of local relapse after breast-conserving surgery, which was made feasible by preoperative chemotherapy. A short overview of current neoadjuvant cytostatic, endocrine, and immunotherapy trials is provided. Future opportunities for tailoring therapy to each individual patient based on early information from the primary tumor are discussed. Important considerations and results of recent endocrine trials that analyzed possible tamoxifen-resistance in subgroups are reported. New opportunities exist to evaluate the efficacy of new cancer drugs more rapidly in the neoadjuvant setting than in the metastatic and adjuvant setting. This approach offers the possibility of monitoring prognostic markers in the primary tumor before, during, and after treatment with specific chemotherapeutic agents. With respect to recent findings of gene-array techniques, it is likely that the advances in this technology will lead to improved prognostic statements. It will show the influence of therapy on gene expression profiles in the course of treatment and might enable us to identify chemoresistance of specific tumors rather early. This could potentially lead to a new direction of cancer therapy.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

High frequency of G/C transversion on p53 gene alterations in breast cancers from Taiwan

p53 gene mutation is a very frequent event in many human cancers and is associated with a poor clinical outcome in breast cancer patients. Analysis of p53 gene mutations can also provide clues to the etiology of tumor formation. The present study was conducted to investigate the p53 mutations in patients with breast cancer from Taiwan. Tumor samples from 119 patients undergoing mastectomy for breast cancer were evaluated. The mutational status of the p53 gene (exons 5-8) was screened by polymerase chain reaction-single strand conformation polymorphism analysis followed by direct sequencing. Of all 119 cases of breast carcinoma, 26 mutations of the p53 gene were found in 22 cases (18.5%). Among these mutations, 78% (20/26) were point mutations with the majority of those being missense mutations (75%, 15 of 20 mutations) and the other 22% (6/26) were frameshift mutations. No significant correlation between p53 mutations and clinicopathological features was found, including HER2 status. Moreover, our results disclosed distinct mutation spectra in excess transversions to transitions (15/21, 71.4% vs. 6/21, 28.6%) with GC to CG dominant (6/15, 40%). Mutation hot spots we identified at codons 167, 185, 186, 210, 265 and 295 have rarely been documented in the literature. These findings showed that p53 gene mutation might contribute to the pathogenesis of breast carcinoma. Furthermore, the different mutation spectrum with high transversions in G:C to C:G may imply that the exogenous mutagens outweigh the endogenous processes in breast cancer in patients in Taiwan.

DNA repair and breast carcinoma susceptibility in women

BACKGROUND

Breast carcinoma is the most common cancer and the second leading cause of cancer-related deaths among women. The disease represents approximately 31% of all cancers in Puerto Rican women. Several DNA repair pathways are involved in preventing carcinogenesis. The current study evaluated the hypothesis that a reduced DNA repair capacity (DRC) is a susceptibility factor for breast carcinoma.

METHODS

A retrospective case-control clinical study was performed to compare age-matched DRC in 33 women with histopathologically confirmed breast carcinoma (cases) and 47 cancer-free women (controls). DRC was measured using a host cell reactivation assay with a luciferase reporter gene and then transfected into human peripheral lymphocytes. A questionnaire was used to solicit breast carcinoma risk factors.

RESULTS

Women with breast carcinoma had a mean DRC of 5.6% +/- 0.5 standard error of the mean (SEM). Cancer cases had a 36% reduction (P<0.001) in DRC when compared with the control group (DRC=8.7% +/- 0.7 SEM). Younger participants with breast carcinoma were found to have a more significant reduction in DRC when compared with age-matched controls. Family (odds ratio [OR]=4.1), maternal lineage (OR=5.5), and maternal (OR=12.4) history of breast carcinoma were found to be the only statistically significant (P<0.05) risk factors associated with the disease.

CONCLUSIONS

The findings supported the hypothesis that a low DRC is a susceptibility factor for breast carcinoma. A 1% decrease in DRC corresponded to a 22% increase in breast carcinoma risk. To the authors' knowledge, the current study was the first to directly determine the DRC of women with breast carcinoma. Because DRC is an independent risk factor for breast carcinoma, the DRC of women may be a useful marker in predicting susceptibility.

Prognostic value of p53 molecular status in high-risk primary breast cancer

BACKGROUND

Mutations in the p53 gene are the most common genetic alterations in human primary breast carcinoma and these mutations are often associated with worse prognosis and chemo/radioresistance.

PATIENTS AND METHODS

The analysis of the p53 gene was performed by fluorescence-assisted mismatch analysis in 13 consecutive high-risk primary breast cancer (HR-BC) patients with 10 or more involved axillary nodes to evaluate its prognostic value.

RESULTS

Three p53 mutations (23%) and four allelic variants were detected. After a median follow-up of 52 months the HR-BC disease-free survival (DFS) was 51% and overall survival 79%. All patients harboring a p53 mutation (p53(mut)) relapsed within 10 months of the median DFS while 67% of those showing a wild-type p53 status (p53(wt)) survive disease-free at a median follow-up of 43 months. One p53(mut) patient is still alive while all the p53(wt) patients survive at 56 months median follow-up. Two out of the four p53(wt) relapsing breast cancer patients showed the Arg72Pro allelic variant; one of these died at 75 months.

CONCLUSIONS

p53 mutations may help identify a subset of very high risk breast cancer patients (vHR-BC) with worse prognosis.

Comparison of p53 mutational status with mRNA and protein expression in a panel of 24 human breast carcinoma cell lines

We analyzed the p53 mutational status, mRNA and protein expression in 24 human breast carcinoma cell lines. Following measurement of their DNA content with flow cytometry, we ascertained the copy numbers of the centromere of chromosome 17 (cen17) and p53 with fluorescence in situ hybridization (FISH). A functional yeast assay (FASAY) was used to screen for inactivating mutations. Positive results were subsequently verified by DNA sequencing. Finally, we assessed the mRNA expression with a competitive reverse transcription-polymerase chain reaction (RT-PCR) assay and the protein expression with immunocytochemical staining, western blot, and quantitative flow cytometry. The DNA content of the cell lines ranged from 0.85 to 2.58. Nine cell lines had concordant copy numbers (between two and four) of p53 and cen17, whereas 12 had more, and three less cen17 than p53 copies. The FASAY was successful in all but one cell line and revealed the presence of mutated alleles in 16 of them, 13 cell lines expressed only the mutated, and three both the mutated and the wild-type alleles. The mutations were comprised of 11 missense, two nonsense, and three frameshift mutations. Immunocytochemical staining, western blot and quantitative flow cytometry yielded comparable p53 protein expression results. However, both the mRNA and the protein expression levels varied considerably in the different cell lines and no consistent pattern with regard to the respective p53 mutational status became evident. The results obtained in these breast carcinoma cell lines indicate that no clear-cut linear relationship exists between the p53 mutational status and the extent of its respective mRNA and protein expression. Therefore, direct DNA analyses and functional assays remain the only methods for the reliable detection of p53 mutations.

TP53 and breast cancer

The TP53 gene (p53) is found altered in breast carcinomas in approximately 20-40% of all cases depending on tumor size and stage of the disease. It seems to be an early event in breast tumorigenesis. Several polymorphisms in the TP53 gene have been detected and their possible roles in breast cancer risk and association to type of cancer developed are discussed. The different mutation spectra seen in geographical and ethnic populations may be used to identify environmental exposure contributing to breast cancer development. The role of TP53 mutation as a prognostic marker is reviewed as well as its role as a predictor for therapy response. All data available on TP53 mutation analyses of human breast carcinomas, as well data from transgenic animal studies and experimental cell studies, support an important role for TP53 in mammary carcinogenesis.

Correlations of Breast Carcinoma Biomarkers and p53 Tested by FASAY and Immunohistochemistry

p53 status is an important predictive factor in breast cancer, but the results of many studies are ambiguous. We tested p53 by functional analysis of separated alleles in yeast (FASAY) as well as by immunohistochemistry (IHC) and evaluated correlations with main prognostic factors, proliferation, and Bcl-2. Thirty-two tumors were tested with antibodies BP53-12, DO1, DO11, DO12, and by FASAY. Spearman rank correlations were tested separately with age, tumor type, pT, grade, pN, NPI, Ki-67, S-phase, proliferation index, Bcl-2, and steroid receptor status determined by ER, PR, and pS2. FASAY showed significant correlations with ductal type, grade and proliferation, and an inverse correlation with functional estrogen receptor and Bcl-2. FASAY provided better correlations compared to p53 IHC. We conclude that FASAY shows significant correlations with main prognostic/predictive factors and provides more reliable biological information compared to p53 IHC. Apoptosis is positively linked to proliferation and is not under the control of p53, which is frequently mutated in highly proliferating carcinomas. FASAY seems to be very important in assessing the predictive significance of p53 for a specific therapy of breast cancer.

p53 immunohistochemical scoring: an independent prognostic marker for patients after hepatocellular carcinoma resection

AIM: To confirm if p53 mutation could be a routine predictive marker for the prognosis of hepatocellular carcinoma (HCC) patients.

METHODS: Two hundreds and forty-four formalin-fixed paraffin-embedded tumor samples of the patients with HCC receiving liver resection were detected for nuclear accumulation of p53. The percent of p53 immunoreactive tumor cells was scored as 0 to 3 + in p53 positive region (< 10% -, 10%-30% +, 31%-50% ++, > 50% +++). Proliferating cell nuclear antigen (PCNA) and some clinicopathological characteristics, including patients’ sex, preoperative serum AFP level, tumor size, capsule, vascular invasion (both visual and microscopic), and Edmondson grade were also evaluated.

RESULTS: In univariate COX harzard regression model analysis, tumor size, capsule status, vascular invasion, and p53 expression were independent factors that were closely related to the overall survival (OS) rates of HCC patients. The survival rates of patients with 3+ for p53 expression were much lower than those with 2+ or + for p53 expression. Only vascular invasion (P < 0.05) and capsule (P < 0.01) were closely related to the disease-free survival (DFS) of HCC patients. In multivariate analysis, p53 overexpression (RI 0.5456, P < 0.01) was the most significant factor associated with the OS rates of patients after HCC resection, while tumor size (RI 0.5209, P < 0.01), vascular invasion (RI 0.5271, P < 0.01) and capsule (RI 0.8691, P < 0.01) were also related to the OS. However, only tumor capsular status was an independent predictive factor (P < 0.05) for the DFS. No significant prognostic value was found in PCNA-LI, Edmondson’s grade, patients’ sex and preoperative serum AFP level.

CONCLUSION: Accumulation of p53 expression, as well as tumor size, capsule and vascular invasion, could be valuable markers for predicting the prognosis of HCC patients after resection. The quantitative immunohistochemical scoring for p53 nuclear accumulation might be more valuable for predicting prognosis of patients after HCC resection than the common qualitative analysis.

The prognostic molecular markers in hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) still remains dismal, although many advances in its clinical study have been made. It is important for tumor control to identify the factors that predispose patients to death. With new discoveries in cancer biology, the pathological and biological prognostic factors of HCC have been studied quite extensively. Analyzing molecular markers (biomarkers) with prognostic significance is a complementary method. A large number of molecular factors have been shown to associate with the invasiveness of HCC, and have potential prognostic significance. One important aspect is the analysis of molecular markers for the cellular malignancy phenotype. These include alterations in DNA ploidy, cellular proliferation markers (PCNA, Ki-67, Mcm2, MIB1, MIA, and CSE1L/CAS protein), nuclear morphology, the p53 gene and its related molecule MD M2, other cell cycle regulators (cyclin A, cyclin D, cyclin E, cdc2, p27, p73), oncogenes and their receptors (such as ras, c-myc, c-fms, HGF, c-met, and erb-B receptor family members), apoptosis related factors (Fas and FasL), as well as telomerase activity. Another important aspect is the analysis of molecular markers involved in the process of cancer invasion and metastasis. Adhesion molecules (E-cadherin, catenins, serum intercellular adhesion molecule-1, CD44 variants), proteinases involved in the degradation of extracellular matrix (MMP-2, MMP-9, uPA, uPAR, PAI), as well as other molecules have been regarded as biomarkers for the malignant phenotype of HCC, and are related to prognosis and therapeutic outcomes. Tumor angiogenesis is critical to both the growth and metastasis of cancers including HCC, and has drawn much attention in recent years. Many angiogenesis-related markers, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived endothelial cell growth factor (PD-ECGF), thrombospondin (TSP), angiogenin, pleiotrophin, and endostatin (ES) levels, as well as intratumor microvessel density (MVD) have been evaluated and found to be of prognostic significance. Body fluid (particularly blood and urinary) testing for biomarkers is easily accessible and useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum, and its genetic alterations in HCC are other important trends. More attention should be paid to these two areas in future. As the progress of the human genome project advances, so does a clearer understanding of tumor biology, and more and more new prognostic markers with high sensitivity and specificity will be found and used in clinical assays. However, the combination of some items, i.e., the pathological features and some biomarkers mentioned above, seems to be more practical for now.

Validation of p53 immunohistochemistry as a prognostic factor in breast cancer in clinical practice

CONTEXT

Abnormal p53 tumor suppressor gene expression as detected by immunohistochemistry is a possible prognostic factor in breast cancer. The difference in techniques used to evaluate the expression of mutated p53 protein is under intense scrutiny, as well as its uses either independently or in conjunction with other prognostic factors in breast cancer.

OBJECTIVE

To determine whether p53 immunohistochemistry can be used as a reliable indicator of the presence of mutated nuclear p53 protein, and whether this method can be performed reliably in a community hospital's clinical practice.

DESIGN

ne hundred twenty-two cases of breast carcinoma were stained and analyzed for the presence of p53 protein using DO-7 (Dako Corporation, Carpinteria, Calif) p53 antibody.

RESULTS

Of the 122 cases of invasive carcinoma studied, 23 (18.7%) were positive for p53, and 16 (16.3%) of 98 cases with coexisting ductal carcinoma in situ were positive for p53. This finding is in agreement with comparable published studies.

CONCLUSIONS

Based on the results of this study, we conclude that p53 immunohistochemistry qualifies as a diagnostic technique suitable for clinical practice in a community hospital. Its detection may be particularly promising in clinical trials of new molecular therapies directed at the p53 tumor suppressor gene.

p53 as a mutagen test in breast cancer

The p53 gene is mutated in about half of all tumors. The p53 gene can be used as a "mutagen test," that is, the relative frequencies of the different types of mutation can be used as an epidemiological tool to explore the contribution of exogenous mutagens vs. endogenous processes in particular cancers. p53 has been used as a mutagen test in breast cancer. Surprisingly, the pattern of p53 mutations differs among 15 geographically and ethnically diverse populations. In contrast, mutation patterns in the human factor IX gene are similar in geographically and ethnically diverse populations. Diverse p53 mutation patterns in breast cancer are consistent with a significant contribution by a diversity of exogenous mutagens. Breast tissue may be uniquely sensitive to lipophilic mutagens because of its unique architecture, characterized by tiny islands of cancer-prone mammary epithelial cells surrounded by a sea of adipocytes. Mammary epithelial cells may be differentially susceptible to released lipophilic mutagens preferentially concentrated in adjacent adipocytes and originating in the diet. To test this hypothesis, we developed a method for measuring mutation load from ethanol-fixed, paraffin-embedded human tissues immunohistochemically stained with anti-p53 antibodies. Single cells staining positively for p53 overabundance are microdissected and the gene is sequenced. It is possible to identify individuals with a high mutation load in normal breast tissue and who are presumably at increased risk for breast cancer. In addition, analysis of the p53 gene with appropriate mutation detection methodology markedly improves the prediction of early recurrence, treatment failure, and death in breast cancer patients. Mutagen tests and mutation load measurements are useful tools to identify the role of mutagens in breast cancer.

Prognostic value of TP53 gene mutation in adjuvant treated breast cancer patients

We investigated the prognostic significance of mutation to the TP53 tumor suppressor gene in a series of 908 breast cancer patients treated with or without adjuvant therapies. The frequency of TP53 mutation detected by single strand conformation polymorphism (SSCP) was 19.4% (176/908) in the overall tumor series. In multivariate analysis, TP53 mutation was independently associated with worse survival in the overall (HR = 2.1, 95% CI [1.5-3.1], P<0.0001), non-adjuvant treated (HR=2.2, 95% CI [1.2-4.2], P=0.017) and adjuvant treated (HR= 2.0, 95% CI [1.3-3.1], P = 0.0009) patients.

A targeted mouse Brca1 mutation removing the last BRCT repeat results in apoptosis and embryonic lethality at the headfold stage

A mouse model with a targeted mutation in the 3' end of the endogenous Brca1 gene, Brca1(1700T), was generated to compare the phenotypic consequences of truncated Brca1 proteins with other mutant Brca1 models reported in the literature to date. Mice heterozygous for the Brca1(1700T) mutation do not show any predisposition to tumorigenesis. Treatment of these mice with ionizing radiation or breeding with Apc, Msh-2 or Tp53 mutant mouse models did not show any change in the tumor phenotype. Like other Brca1 mouse models, the Brca1(1700T) mutation is embryonic lethal in homozygous state. However, homozygous Brca1(1700T) embryos reach the headfold stage but are delayed in their development and fail to turn. Thus, in contrast to Brca1(null) models, the mutant embryos do not undergo growth arrest leading to a developmental block at 6.5 dpc, but continue to proliferate and differentiate until 9.5 dpc. Homozygous embryos die between 9.5-10.5 dpc due to massive apoptosis throughout the embryo. These results indicate that a C-terminal truncating Brca1 mutation removing the last BRCT repeat has a different effect on normal cell function than does the complete absence of Brca1.

Mutation analysis of p53 in ovarian tumors by DHPLC

Up to now, ovarian carcinomas represent a major health problem among female cancers because they are the leading cause of death from gynecological malignancy. A high proportion of these tumors selects for mutations in the p53 gene. There is evidence that inactivation of the p53 protein could indicate poor prognosis and chemoresistance of patients. To set up a fast and sensitive test for p53 defects in tumor tissues, we analyzed ovarian cancer cells by denaturing high-performance liquid chromatography (DHPLC). A primer set spanning the whole coding region of p53 with seven fragments was designed and appropriate heteroduplex detection in DHPLC analysis was elaborated. The analysis of 45 ovarian tumor specimens yielded 17 genetic alterations (38%) occurring exclusively in the malignant tissue of the patients. In addition, frequent polymorphisms present in normal compared to tumor tissue could serve as a tool for the rapid identification of loss of heterozygosity (LOH) in the tumor. We observed that LOH in intron 2 or 3 correlated well with a lack of one allele in mutated fragments. In conclusion, DHPLC screening appears to be a sensitive and effective test for genetic alterations in tumors with p53 involvement. Since p53 mutations point to a poor prognosis state in several cancers, a fast screening of tumor material for genetic variations may have implications for further individual treatment of patients.