Comparison between p53 protein measurements using the luminometric immunoassay and immunohistochemistry with detection of p53 gene mutations using cDNA sequencing in human breast tumors

The 40bp Indel Polymorphism rs150550023 in the MDM2 Promoter is Associated with Intriguing Shifts in Gene Expression in the p53-MDM2 Regulatory Hub

Most low-penetrance genetic risk factors for cancer are located in noncoding regions, presumably altering the regulation of neighboring genes. The poorly characterized Indel polymorphism rs150550023 (rs3730485; del1518) in the promoter of MDM2 (human homolog of mouse double minute 2) is a biologically plausible candidate genetic risk factor, which might influence the expression of MDM2, a key negative regulator of the central tumor suppressor p53. Here, we genotyped rs150550023 in a Central European hospital-based case-control study of 407 breast cancer patients and 254 female controls. mRNA levels of MDM2, p53, and the p53 target genes p21, BAX, and PERP were quantified with qRT-PCR, and p53 protein was assessed with immune histochemistry in ≈100 primary breast tumors with ascertained rs150550023 genotype. We found no evidence for an association of rs150550023 with the risk, age at onset, or prognosis of breast cancer. A possible synergism was observed with SNP309 in promoter P2 of MDM2. Mean mRNA levels of MDM2, p53, p21, and BAX were ≈1.5-3 fold elevated in TP53 wildtype tumors with the minor homozygous Del/Del genotype. However, systematic shifts in p53 protein levels or mutation rates were not observed, suggesting that the elevated p53 mRNA levels are due to regulatory feedback loops that compensate for the effects of rs150550023 on MDM2 expression.

Clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA from breast cancer patients in China

Background

TP53 mutations are common in breast cancer. There is currently no large‐scale cohort study to investigate the TP53 landscape in breast cancer patients from China. The predictive value of TP53 mutations for the efficacy of human epidermal growth factor receptor 2 (HER2)‐targeted therapy in breast cancer remains controversial. In the present study, we aimed to analyze the clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA (ctDNA) from breast cancer patients in China.

Methods

We retrospectively analyzed the clinical data and TP53 mutation features in ctDNA samples from 804 patients with metastatic breast cancer. TP53 mutations were detected by target region capture‐based next‐generation sequencing. The relationship between TP53 mutation status and disease‐free survival (DFS) was analyzed in 444 patients with metastatic breast cancer. Moreover, the relationship between TP53 mutation status and progression‐free survival (PFS) was analyzed in 55 HER2‐positive patients treated with first‐line trastuzumab‐based therapy. Kaplan‐Meier analysis was performed to estimate the survival curves of the different subgroups, and the log‐rank test was used to compare the curves. A Cox regression model was used to estimate multivariable‐adjusted hazard ratios and their 95% confidence intervals (CIs) associated with the DFS and PFS.

Results

Among the 804 investigated patients, 431 (53.6%) patients harbored TP53 mutations. TP53 mutations were differentially distributed among different molecular subtypes of breast cancer (P < 0.05). Patients with TP53 mutations had a shorter DFS than those with wild‐type TP53 (hazard ratio = 1.32, 95% CI = 1.09‐1.61, P = 0.005). TP53 mutations in exons 5‐8 were associated with worse outcome (hazard ratio = 1.50, 95% CI = 1.11‐2.03, P = 0.009). However, TP53 mutation status was not significantly associated with PFS in HER2‐positive patients who received first‐line trastuzumab‐based therapy (P = 0.966). Interestingly, in the taxane combination group, patients with TP53 mutations exhibited longer PFS than those without TP53 mutations (hazard ratio = 0.08, 95% CI = 0.02‐0.30, P < 0.001). However, in the non‐taxane combination group, patients with TP53 mutations displayed shorter PFS than those with wild‐type TP53 (hazard ratio = 4.84, 95% CI = 1.60‐14.66, P = 0.005).

Conclusions

TP53 mutations in exons 5‐8 may be an independent prognostic marker for short DFS in patients with metastatic breast cancer. TP53 mutations had opposite effects on trastuzumab‐treated patients treated with and without taxanes.

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.

Association of the MDM2 SNP285 and SNP309 Genetic Variants with the Risk, Age at Onset and Prognosis of Breast Cancer in Central European Women: A Hospital-Based Case-Control Study

SNP309T>G (rs2279744) and SNP285G>C (rs117039649) in the MDM2 promoter are thought to have opposite effects on the binding of transcription factor SP1 (specificity protein 1), and consequently on MDM2 expression, p53 levels, cancer risk, age at onset, and prognosis. Here, we genotyped SNP309 and SNP285 in 406 Austrian breast cancer patients and 254 female controls. The SNP309GG genotype was associated with an increased breast cancer risk in p53 negative (OR, 1.82; 95% CI, 1.09–3.03; p = 0.02), but not p53 positive or unselected patients. In contrast, the SNP309TT genotype was associated with an earlier age at onset (TT, 57.0 ± 12.9; TG, 58.6 ± 13.9; GG, 59.7 ± 15.0 years; p = 0.048). 31% of SNP309TT, 26% of TG, and 13% of GG tumors were p53 positive (p = 0.034), indicating a lower selective pressure to mutate TP53 in the presence of the G-allele. Moreover, SNP309TT patients exhibited a shortened metastasis-free survival in multivariable analysis. Censoring carriers of the SNP285C-allele hardly altered the strength of these associations of SNP309, thus challenging the proposed antagonistic function of SNP285C towards SNP309G. The minor SNP285C-allele tended to be non-significantly associated with an increased breast cancer risk and a poor disease-free and metastasis-free survival, which may be bystander effects of its complete linkage disequilibrium with SNP309G. We conclude that the SNP309G-allele attenuates the p53-response and leads to a higher breast cancer risk, but also to a later onset of breast cancer and a trend towards a good prognosis.

Prognostic value of immunohistochemically detected p53 in adjuvant chemotherapy-treated triple negative breast cancer

Mutations of the p53 gene are the most common genomic alterations associated with triple-negative breast cancer (TNBC) and are reported in 60-88% cases. Despite the high incidence of such mutations, there is no consensus about the clinical application of p53 detection in breast cancer management. This study investigates the prognostic value of immunohistochemically detected p53 in TNBC patients who received adjuvant chemotherapy. We reviewed the clinicopathologic features of 1088 TNBC patients who received curative surgery and adjuvant chemotherapy. Immunohistochemically, nuclear staining of >10% was defined as p53 "positive." Of the total 1088 TNBC patients, 709 (65.2%) had no lymph node metastasis (N0). Among the N0 patients, 408 (57.5%) were p53- positive (p53+), and 301 (42.5%) were p53- negative (p53-). p53 + tumors showed a tendency for better breast cancer-specific survival (BCSS, p = 0.052) and overall survival (OS, p = 0.079) compared to p53- tumors. In multivariate analysis, p53 + tumors showed significantly better BCSS (p53 + vs. p53-; HR 2.8, 95% confidence interval: 1.1-7.3, p = 0.034); however, in TNBC patients with lymph node metastasis, there was no correlation between p53 status, clinicopathologic characteristics, and survival. Consequently, in TNBC patients who received adjuvant chemotherapy, immunohistochemical p53 expression was associated with better BCSS in N0 patients.

Medullary Breast Carcinoma: Prognostic Implications of P53 Expression

Medullary breast carcinoma (MBC) is a rare pathological type of breast cancer. The rate of p53 protein accumulation is higher in MBC than in common invasive ductal carcinoma. Whether this particular feature of MBC influences the outcome after treatment is unknown. We retrospectively analyzed the characteristics, treatment and outcome of 71 patients with MBC treated between 1981 and 1996. The median age was 51 years (range 27–81) and the median clinical tumor size was 25 mm (range 0-70 mm). Breast-conserving treatment was offered when possible: 55 patients had undergone a tumorectomy and radiotherapy while 16 patients had undergone a mastectomy. p53 protein accumulation was determined by immunohistochemistry on paraffin-embedded tumor specimens from 58/71 samples available for this study. The median follow-up for the 56 survivors was 113 months (range 30–241). The 10-year survival and metastasis-free survival rates were 81% and 81.4%, respectively. The local recurrence rate was 16.4%. The two factors predicting outcome were pathological axillary node involvement in the 60 patients who underwent axillary dissection and adjuvant chemotherapy. p53 accumulation was found in 33/58 patients (57%). p53 status was not predictive of survival nor of distant or local recurrences. We confirm that medullary breast carcinoma has a favorable prognosis despite its aggressive pathological features. p53 protein accumulation, found in the majority of MBCs, was not related to outcome.

Current Approaches to Diagnosis and Treatment of Ductal Carcinoma In Situ and Future Directions

The presentation and treatment of ductal carcinoma in situ (DCIS) has changed substantially over the years. While previously an incidental pathologic finding in more advanced, palpable tumors, the institution of screening mammography has repositioned this disease entity as one largely diagnosed as a non-palpable lesion, often prior to any invasive disease. As DCIS is a precursor to invasive carcinoma, evolution in the approach to treatment has followed in the footsteps of that for invasive disease, including breast conservation therapy, adjuvant radiation, and use of antihormonal therapy. Survival outcomes for DCIS are very high and more recent literature has investigated tailoring therapeutic approaches to avoid overtreatment. Two important areas of ongoing clinical debate concerning overtreatment include use of preoperative MRI and the role of adjuvant radiation. The heterogeneity of the disease makes it difficult to differentiate lesions that would benefit from more aggressive treatment from those in which overtreatment could be avoided. Clinical characteristics, such as histologic appearance, age at diagnosis, and margin status at tumor excision have been established as moderate predictors of disease recurrence, but none has provided strong enough evidence as to guide consensus decisions on adjuvant therapy. Continuing research seeks to define the genetic and molecular characteristics that can predict disease course and serve as the potential targets for novel therapeutic agents. While several markers have shown promise in differentiating tumor aggressiveness, there is still much to be discovered about the precise mechanisms of disease progression and how this can be applied clinically to optimize treatment.

TP53-based interaction analysis identifies cis-eQTL variants for TP53BP2, FBXO28, and FAM53A that associate with survival and treatment outcome in breast cancer

TP53 overexpression is indicative of somatic TP53 mutations and associates with aggressive tumors and poor prognosis in breast cancer. We utilized a two-stage SNP association study to detect variants associated with breast cancer survival in a TP53-dependent manner. Initially, a genome-wide study (n = 575 cases) was conducted to discover candidate SNPs for genotyping and validation in the Breast Cancer Association Consortium (BCAC). The SNPs were then tested for interaction with tumor TP53 status (n = 4,610) and anthracycline treatment (n = 17,828). For SNPs interacting with anthracycline treatment, siRNA knockdown experiments were carried out to validate candidate genes.In the test for interaction between SNP genotype and TP53 status, we identified one locus, represented by rs10916264 (p(interaction) = 3.44 × 10-5; FDR-adjusted p = 0.0011) in estrogen receptor (ER) positive cases. The rs10916264 AA genotype associated with worse survival among cases with ER-positive, TP53-positive tumors (hazard ratio [HR] 2.36, 95% confidence interval [C.I] 1.45 - 3.82). This is a cis-eQTL locus for FBXO28 and TP53BP2; expression levels of these genes were associated with patient survival specifically in ER-positive, TP53-mutated tumors. Additionally, the SNP rs798755 was associated with survival in interaction with anthracycline treatment (p(interaction) = 9.57 × 10-5, FDR-adjusted p = 0.0130). RNAi-based depletion of a predicted regulatory target gene, FAM53A, indicated that this gene can modulate doxorubicin sensitivity in breast cancer cell lines.If confirmed in independent data sets, these results may be of clinical relevance in the development of prognostic and predictive marker panels for breast cancer.

Prognostic value of Ki67 and p53 in patients with estrogen receptor-positive and human epidermal growth factor receptor 2-negative breast cancer: Validation of the cut-off value of the Ki67 labeling index as a predictive factor

The aim of this study was to evaluate the significance of the Ki67 labeling index and p53 status as prognostic and predictive indicators of operable estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Among 697 consecutive patients with primary breast cancer who underwent curative surgery between 2002 and 2013, 308 patients with ER-positive and HER2-negative breast cancer were assessed. The results of the multivariate Cox analysis demonstrated that a high Ki67 labeling index was significantly associated with a short recurrence-free interval (RFI) (p=0.004) and was marginally associated with a worse overall survival (p=0.074). A positive p53 status was not associated with worse outcomes. To validate the cut-off values of the Ki67 labeling index for identifying patients who may benefit from additional chemotherapy, prognostic factors were investigated in breast cancer patients treated postoperatively with endocrine therapy alone. Analysis of receiver operating characteristic curves demonstrated that a Ki67 labeling index cut-off of 20.0% was optimal for predicting recurrence among patients who did not receive adjuvant chemotherapy. The 5-year RFIs for patients with Ki67 <20 and ≥20% were 97.2 and 86.6%, respectively (p=0.0244). A high Ki67 labeling index (≥20%) was significantly associated with large tumors (p<0.01), lymph node metastasis (p=0.0236) and positive p53 status (p<0.001). The univariate analysis demonstrated that Ki67 labeling index ≥20%, lymph node metastasis and progesterone receptor negativity were significant worse prognostic factors for RFI (p=0.0333, 0.0116 and 0.0573, respectively). The Ki67 labeling index was found to be a useful prognostic factor in patients with ER-positive and HER2-negative breast cancer and the cut-off values of the Ki67 labeling index for making a decision regarding adjuvant treatment were validated.

Deletion/duplication mutation screening of TP53 gene in patients with transitional cell carcinoma of urinary bladder using multiplex ligation-dependent probe amplification

Bladder cancer is a molecular disease driven by the accumulation of genetic, epigenetic, and environmental factors. The aim of this study was to detect the deletions/duplication mutations in TP53 gene exons using multiplex ligation-dependent probe amplification (MLPA) method in the patients with transitional cell carcinoma (TCC). The achieved formalin-fixed paraffin-embedded tissues from 60 patients with TCC of bladder were screened for exonal deletions or duplications of every 12 TP53 gene exons using MLPA. The pathological sections were examined by three pathologists and categorized according to the WHO scoring guideline as 18 (30%) grade I, 22 (37%) grade II, 13 (22%) grade III, and 7 (11%) grade IV cases of TCC. None mutation changes of TP53 gene were detected in 24 (40%) of the patients. Furthermore, mutation changes including, 15 (25%) deletion, 17 (28%) duplication, and 4 (7%) both deletion and duplication cases were observed among 60 samples. From 12 exons of TP53 gene, exon 1 was more subjected to exonal deletion. Deletion of exon 1 of TP53 gene has occurred in 11 (35.4%) patients with TCC. In general, most mutations of TP53, either deletion or duplication, were found in exon 1, which was statistically significant. In addition, no relation between the TCC tumor grade and any type of mutation were observed in this research. MLPA is a simple and efficient method to analyze genomic deletions and duplications of all 12 exons of TP53 gene. The finding of this report that most of the mutations of TP53 occur in exon 1 is in contrast to that of the other reports suggesting that exons 5-8 are the most (frequently) mutated exons of TP53 gene. The mutations of exon 1 of TP53 gene may play an important role in the tumorogenesis of TCC.

Histopathology and Prognostic Indices of Carcinoma Breast with Special Reference to p53 Marker

INTRODUCTION

Cancer of the breast is one of the commonest carcinomas in women, both in western world and in India. The high frequency of breast cancer in women has prompted an intensive study of possible modifiable risk factors (clinical parameters, morphological typing, and biological markers) for assessment of prognosis, prevention strategies, and treatment modalities. p53 is one of the most significant prognostic markers for breast carcinomas.

AIMS AND OBJECTIVES

This study was undertaken to ascertain the prevalence of p53 mutated protein in breast carcinomas by immunohistochemistry and correlating the results with clinical and histological parameters and also determine its influence on axillary node metastasis.

MATERIALS AND METHODS

Clinico-pathological evaluation of 50 cases of infiltrating ductal carcinoma of the breast, with reference to p53 mutated protein expression by means of immunohistochemistry was undertaken.

RESULTS

The percentage positivity of p53 immunohistochemistry of this study was 22% which is similar to the reported statistics of various other studies. The immunohistochemistry results also showed an equivocal p53 status in both the positive and negative cases of lymph node metastases. The carcinomas with p53 positivity demonstrated aggressive characteristics, including larger size, higher grade, in comparison with p53 negative cases. The probability of getting positive p53 status was higher for those with severe lymphocytic reaction of tumours, for patients less than 35 years of age and for those with tumour on the left side. This study clearly indicates that p53 over expression in breast cancers are mostly aggressive tumours and they confer poor prognosis and likelihood of a poor response to endocrine therapy and chemotherapy.

p53 accumulation is a strong predictor of recurrence in estrogen receptor-positive breast cancer patients treated with aromatase inhibitors

Aromatase inhibitors have played a central role in endocrine therapy for estrogen receptor (ER)-positive breast cancer in postmenopausal women. However, factors predictive of the efficacy of aromatase inhibitors, and prognostic factors, both for early and late recurrence in women treated with adjuvant aromatase inhibitors have not been identified. Whole genome analysis identified that a TP53 gene mutation exists in ER-positive breast cancers, although the frequency of TP53 gene mutation in luminal tumors is lower compared with basal-like or human epidermal growth factor receptor type 2 (HER2)-positive breast cancers. We examined expression of p53, as well as ER, progesterone receptor, HER2 and Ki-67 using immunohistochemistry in postmenopausal ER-positive breast cancer patients who were treated with aromatase inhibitors as adjuvant endocrine therapy. There were 53 (21%) tumors that contained 10% or more p53-positive cells. High p53 expression was positively correlated with tumor grade, HER2 score and Ki-67 expression. Significant association was observed between disease-free survival and high p53 expression in multivariate analysis (P < 0.0001). Compared with women without recurrence, women with early recurrence had significantly higher p53 expression (P < 0.0001), as did women with late recurrence (P = 0.037). The present study demonstrates that p53 accumulation is a strong predictor of both early and late recurrence in ER-positive breast cancer patients treated with aromatase inhibitors as adjuvant endocrine therapy. TP53 gene alteration might be a key biological characteristic of ER-positive breast cancer.

Molecular alterations in metaplastic breast carcinoma

Metaplastic carcinoma of the breast is a rare and heterogeneous subtype of breast carcinoma with a generally poor outcome, and few therapeutic options once disease recurs or progresses. Metaplastic carcinomas of the breast are usually of a larger size at diagnosis, with less frequent nodal metastasis compared with invasive ductal carcinoma no special type, and lack hormone and HER2 receptor expression. Recent research has revealed some potentially actionable genetic changes in a subset of these rare tumours. However, ongoing efforts to further characterise the genetic basis and the molecular alterations underlying the distinctive morphological and clinical characteristics of these tumours are needed in order to identify new targets for treatment. This review will describe the theories of pathogenesis of metaplastic breast carcinoma, and highlight genetic changes and potential therapeutic targets in this generally poor prognosis malignancy.

The Pro allele of the p53 codon 72 polymorphism is associated with decreased intratumoral expression of BAX and p21, and increased breast cancer risk

Background

The TP53 Arg72Pro polymorphism encodes two p53 variants with different biochemical properties. Here we investigated the impact of this polymorphism on the expression of key p53 target genes in a panel of human breast carcinomas, breast cancer risk, and age at onset.

Methodology/Principal Findings

The Arg72Pro polymorphism was genotyped in 270 breast cancer patients and 221 control subjects. In addition, the Arg72Pro genotype of 116 breast tumors was determined, and correlated with intratumoral mRNA expression of TP53 and its key target genes MDM2, p21, BAX, and PERP, as quantified by qRT-PCR. We found a significantly increased breast cancer risk associated with the Pro-allele (per-allele odds ratio, 1.46; 95% confidence interval, 1.08–1.99), and a significantly later mean age at breast cancer onset for Pro/Pro patients (63.2±18 years) compared to Arg/Arg patients (58.2±15 years). The frequency of somatic TP53 inactivation was 25.4% in Arg/Arg, 20.9% in Arg/Pro, and 16.7% in Pro/Pro patients, which may reflect a higher selective pressure to mutate the Arg-allele. The median mRNA levels of p21 and BAX in the tumors of Pro-allele carriers were significantly reduced to 55.7% and 76.9% compared to Arg/Arg patients, whereas p53, MDM2 and PERP expression were hardly altered.

Conclusions/Significance

The p53^72Arg variant appears to be a more potent in vivo transcription factor and tumor suppressor in human breast cancer than the p53^72Pro variant. The Arg72Pro genotype has no significant effects in patients with TP53 mutated tumors, in which p53 is non-functional.

Immunohistochemical evaluation of p53 expression with different antibodies in malignant canine tumours with or without p53 gene mutation

Six monoclonal antibodies and a polyclonal antibody (CM1) were used to investigate the overexpression of p53 protein by immunohistochemistry (IHC) in six sarcomas and 21 mammary carcinomas from 27 dogs. IHC was compared with p53 gene mutation analysis performed on the same samples. Only the monoclonal PAb240, PAb421 and the CM1 antibodies were able to detect expression of canine p53 protein. CM1 was found to give the highest concordance (8/11) between positive expression of the p53 protein by IHC and the presence of a gene mutation. In the samples that were negative for p53 expression by IHC, but contained a p53 gene mutation according to DNA analysis, the mutation often affected the epitopes that could have been recognized by these antibodies. Only one out of 16 tumours without a p53 gene mutation had a weakly positive IHC result. These findings indicate that in these two types of canine tumours, IHC - particularly with CM1 - can detect many alterations in p53 expression owing to a gene mutation. False-positive results were very infrequent.

Association of the germline TP53 R72P and MDM2 SNP309 variants with breast cancer survival in specific breast tumor subgroups

The tumor suppressor gene TP53 and its regulator MDM2 are both important players in the DNA-damage repair "TP53 response pathway". Common germline polymorphisms in these genes may affect outcome in patients with tumors characterized by additional somatic changes in the same or a related pathway. To evaluate this hypothesis, we determined the effect of the common germline TP53 R72P and MDM2 SNP309 polymorphisms on breast cancer survival in a consecutive cohort of breast cancer patients (age at diagnosis <53 years, n = 295) with gene expression data available. Patients were classified in subgroups according to their tumor TP53 mutation status and three gene expression profiles; a TP53 mutation status expression signature, a PTEN/PI3K pathway signature and the 70-gene prognosis profile. Survival analyses were performed using Cox regression models adjusting for clinico-pathological characteristics and treatment. An increase in breast cancer-specific mortality was observed for carriers of the germline MDM2 SNP309 rare GG-genotype (range hazard ratios: 2-3) or TP53 R72P heterozygous GC-genotype (range hazard ratios: 1-2) compared to those having the common genotypes within subgroups of tumors displaying a "more aggressive phenotype" gene expression profile. There was no evidence of such an effect on survival within the TP53-mutated tumor group for TP53 R72P carriers but a suggestion of an effect for MDM2 SNP309 carriers (GG vs. TT-genotype HR 2.99, P = 0.06). These results indicate that common polymorphisms in specific pathways may add to the worse prognosis of patients with tumors in which these pathways are affected by somatic alterations.

Evaluation of HER2 and p53 expression in predicting response to docetaxel-based first-line chemotherapy in advanced breast cancer

Background

The human epidermal growth factor receptor 2 (HER2) and p53 pathways may be involved in chemotherapy sensitivity and/or resistance. We explore the value of HER2 and p53 status to foretell docetaxel sensitivity in advanced breast cancer.

Methods

HER2 and p53 expression was analysed in 36 (median age 55 yrs; range 37-87) metastatic breast cancer patients receiving docetaxel-based first-line chemotherapy. HER2 was determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), p53 was tested by IHC. We correlate the expression of study parameters with pathologic parameters, RECIST response and survival. The standard cut-off value of 2 was used to determine HER2 overexpression while p53 mean expression level was used to divide low/high expressors tumors.

Results

Median time to progression and overall survival were 9 (range 2 - 54) and 20 (range 3 - 101) months. Overall response rate was 41.6%. Nine cases showed HER2 overexpression. HER2 was more frequently overexpressed in less differentiated (p = 0.05) and higher stage (p = 0.003) disease. Mean FISH-HER2 values were significantly higher in responder than in non-responder pts (8.53 ± 10.21 vs 2.50 ± 4.12, p = 0.027). Moreover, HER2 overexpression correlates with treatment response at cross-tabulation analysis (p = 0.046). p53 expression was only associated with higher stage disease (p = 0.02) but lack of any significant association with HER status or docetaxel response. No significant relation with survival was observed for any parameter.

Conclusion

Our data seem to indicate that FISH-determined HER2 status but not p53 is associated with docetaxel sensitivity in metastatic breast cancer.

TP53 genomics predict higher clinical and pathologic tumor response in operable early-stage breast cancer treated with docetaxel-capecitabine ± trastuzumab

To determine rates of pathologic complete response (pCR) and near-complete response (npCR) in operable early-stage breast cancer using neoadjuvant capecitabine plus docetaxel, with or without trastuzumab, and investigate biomarkers of pathologic response. Women with operable early-stage breast cancer were enrolled in a multicenter study of neoadjuvant therapy for four 21-day cycles with capecitabine 825 mg/m(2) plus docetaxel 75 mg/m(2) if human epidermal growth factor receptor 2 (HER2)-negative, and additionally, a standard trastuzumab dose if HER2-positive. Primary endpoint was rate of pCR and npCR. Secondary endpoints were potential associations between response and TP53 mutational analysis using the AmpliChip TP53 assay or immunohistochemical (IHC) staining, and genomic subtyping using the PAM50 assay. In patients who completed treatment and surgery, pCR and npCR rates were 15.8% in patients with HER2-negative and 50% in patients with HER2-positive tumors. Stratified by genomic subtype, patients of HER2-enriched subtype had the best response (72.2%), and luminal A (9.1%) and B (4.8%) subtypes, the poorest. Of 147 patients tested for TP53 mutations using the AmpliChip assay, 78 variants were detected; 55 were missense. Response rate among TP53-mutated patients was 30%, significantly higher than TP53 wild-type patients (10%; P = 0.0032). Concordance between AmpliChip mutation status versus TP53 IHC staining was 65%, with AmpliChip status predictive of response and IHC status not predictive. Capecitabine plus docetaxel in HER2-negative, and with trastuzumab in HER2-positive patients, provided a good response rate with four cycles of non-anthracycline-containing therapy. TP53 mutational analysis and genomic subtyping were predictive.

Hormone receptor status rather than HER2 status is significantly associated with increased Ki-67 and p53 expression in triple-negative breast carcinomas, and high expression of Ki-67 but not p53 is significantly associated with axillary nodal metastasis in triple-negative and high-grade non-triple-negative breast carcinomas

Triple-negative (TN) breast carcinoma is associated with a higher recurrence rate and shorter survival and lacks the benefit of specific therapy. TN tumors usually express high levels of Ki-67 and p53 that are considered prognostic markers for breast cancer. We compared Ki-67 and p53 expression between TN and high-grade non-TN invasive carcinomas in a total of 214 cases and investigated an association between their expression and axillary nodal metastasis in these tumors. Our findings demonstrate that TN tumors are associated with significantly higher expression of Ki-67 and p53 compared with non-TN tumors, which may contribute to the poorer prognosis in TN tumors. Hormone receptor negativity rather than HER2 negativity is associated with the significantly increased Ki-67 and p53 expression in TN tumors. Furthermore, a high expression level of Ki-67 but not p53 is more likely to be associated with axillary nodal metastasis in these cases.

Distinct p53 gene signatures are needed to predict prognosis and response to chemotherapy in ER-positive and ER-negative breast cancers

PURPOSE

Estrogen receptor-positive (ER+) and -negative (ER) breast cancers are molecularly distinct diseases. We hypothesized that p53 mutations may lead to different transcriptional changes and carry different prognostic value in these two different types of cancers.

EXPERIMENTAL DESIGN

We developed a 39-gene p53 signature derived from 213 ER+ and a separate 30-gene signature from 38 ER- cancers with known mutation status and tested their prognostic and chemotherapy response predictive values in ER+ and ER- cancers, respectively.

RESULTS

External validation to predict p53 status (n = 103) showed sensitivity and specificity of 89% and 54% for the 39-gene signature, and 82% and 61% for the 30-gene signature. The 39-gene signature was predictive of worse distant metastasis free survival in ER+ cancers in two separate prognostic data sets (n = 255, HR: 2.3, P = 0.005 and n = 198, HR: 2.17, P = 0.09). It also predicted for poor prognosis even with adjuvant tamoxifen therapy (n = 277, HR = 2.43, P < 0.0001) but it was not prognostic in ER- cancers. It was also associated with higher chemotherapy sensitivity in ER+ but not in ER- cancers. The prognostic and predictive values remained significant in multivariate analysis. The 30-gene, ER-, p53 signature showed no prognostic or predictive values in ER+ cancers but it was associated with better prognosis in ER- cancers. It also had no chemotherapy response predictive value in ER- or ER+ cancers.

CONCLUSIONS

P53 dysfunction is prognostically most relevant in ER+ cancers and supports the hypothesis that different predictive or prognostic markers will be needed for different molecular subsets of breast cancer.

Correlation of high 18F-FDG uptake to clinical, pathological and biological prognostic factors in breast cancer

PURPOSE

The aim of this study was to determine the impact of the main clinicopathological and biological prognostic factors of breast cancer on (18)F-fluorodeoxyglucose (FDG) uptake. Only women with tumours larger than 20 mm (T2-T4) were included in order to minimize bias of partial volume effect.

METHODS

In this prospective study, 132 consecutive women received FDG PET/CT imaging before starting neoadjuvant chemotherapy. Maximum standardized uptake values (SUV(max)) were compared to tumour characteristics as assessed on core biopsy.

RESULTS

There was no influence of T and N stage on SUV. Invasive ductal carcinoma showed higher SUV than lobular carcinoma. However, the highest uptake was found for metaplastic tumours, representing 5% of patients in this series. Several biological features usually considered as bad prognostic factors were associated with an increase in FDG uptake: the median of SUV(max) was 9.7 for grade 3 tumours vs 4.8 for the lower grades (p < 0.0001); negativity for oestrogen receptors (ER) was associated with higher SUV (ER+ SUV = 5.5; ER- SUV = 7.6; p = 0.003); triple-negative tumours (oestrogen and progesterone receptor negative, no overexpression of c-erbB-2) had an SUV of 9.2 vs 5.8 for all others (p = 0005); p53 mutated tumours also had significantly higher SUV (7.8 vs 5.0; p < 0.0001). Overexpression of c-erbB-2 had no effect on the SUV value.

CONCLUSION

Knowledge of the factors influencing uptake is important when interpreting FDG PET/CT scans. Also, findings that FDG uptake is highest in those patients with poor prognostic features (high grade, hormone receptor negativity, triple negativity, metaplastic tumours) is helpful to determine who are the best candidates for baseline staging.

Impact of BCL2 and p53 on postmastectomy radiotherapy response in high-risk breast cancer. A subgroup analysis of DBCG82 b&c

PURPOSE

To examine p53 and BCL2 expression in high-risk breast cancer patients randomized to postmastectomy radiotherapy (PMRT).

PATIENTS AND METHODS

The present analysis included 1 000 of 3 083 high-risk breast cancer patients randomly assigned to PMRT in the DBCG82 b&c studies. Tissue microarray sections were stained with immunohistochemistry for p53 and BCL2. Median potential follow-up was 17 years. Clinical endpoints were locoregional recurrence (LRR), distant metastases (DM), overall mortality, and overall survival (OS). Statistical analyses included Kappa statistics, chi(2) or exact tests, Kaplan-Meier probability plots, Log-rank test, and Cox univariate and multivariate regression analyses.

RESULTS

p53 accumulation was not significantly associated with increased overall mortality, DM or LRR probability in univariate or multivariate Cox regression analyses. Kaplan-Meier probability plots showed reduced OS and improved DM and LRR probabilities after PMRT within subgroups of both p53 negative and p53 positive patients. Negative BCL2 expression was significantly associated with increased overall mortality, DM and LRR probability in multivariate Cox regression analyses. Kaplan-Meier probability plots showed a significantly improved overall survival after PMRT for the BCL2 positive subgroup, whereas practically no survival improvement was seen after PMRT for the BCL2 negative subgroup. In multivariate analysis of OS, however, no significant interaction was found between BCL2 and randomization status. Significant reductions in LRR probability after PMRT were recorded within both the BCL2 positive and BCL2 negative subgroups.

CONCLUSION

p53 was not associated with survival after radiotherapy in high-risk breast cancer, but BCL2 might be.

Association of TP53 codon 72 polymorphism and the outcome of adjuvant therapy in breast cancer patients

INTRODUCTION

Single-nucleotide polymorphisms (SNPs) in codon 72 of the TP53 (also known as p53) gene (rs1042522) and in the promoter region of the MDM2 gene (SNP309; rs2279744) have been suggested to play roles in many cancers. We investigated whether these SNPs were associated with patient outcome and the effect of adjuvant systemic therapy.

METHODS

The genotypes of TP53 codon 72 and MDM2 SNP309 were defined among 557 primary Japanese breast cancer patients (median follow-up, 61.7 months). The effects of several variables on survival were tested by Cox's proportional hazards regression analysis.

RESULTS

We showed that the Pro/Pro genotype of TP53 codon 72 was associated with poorer disease-free survival (DFS) than other genotypes by Kaplan-Meier analysis (P = 0.049) and multivariate Cox's proportional hazards regression analysis (P = 0.047, risk ratio of recurrence = 1.67), whereas MDM2 SNP309 status was not associated with DFS. The association of the Pro/Pro TP53 genotype with poorer DFS was especially significant in patients who received adjuvant chemotherapy (P = 0.009). In contrast, among the patients who had received adjuvant hormonal therapy or no adjuvant systemic therapy, TP53 codon 72 genotype was not associated with DFS.

CONCLUSION

The Pro/Pro genotype of TP53 codon 72 appears to be an independent prognostic marker in breast cancer patients.

Molecular subtypes of breast cancer in relation to paclitaxel response and outcomes in women with metastatic disease: results from CALGB 9342

INTRODUCTION

The response to paclitaxel varies widely in metastatic breast cancer. We analyzed data from CALGB 9342, which tested three doses of paclitaxel in women with advanced disease, to determine whether response and outcomes differed according to HER2, hormone receptor, and p53 status.

METHODS

Among 474 women randomly assigned to paclitaxel at a dose of 175, 210, or 250 mg/m2, adequate primary tumor tissue was available from 175. Immunohistochemistry with two antibodies and fluorescence in situ hybridization were performed to evaluate HER2 status; p53 status was determined by immunohistochemistry and sequencing. Hormone receptor status was obtained from pathology reports.

RESULTS

Objective response rate was not associated with HER2 or p53 status. There was a trend toward a shorter median time to treatment failure among women with HER2-positive tumors (2.3 versus 4.2 months; P = 0.067). HER2 status was not related to overall survival (OS). Hormone receptor expression was not associated with differences in response but was associated with longer OS (P = 0.003). In contrast, women with p53 over-expression had significantly shorter OS than those without p53 over-expression (11.5 versus 14.4 months; P = 0.002). In addition, triple negative tumors were more frequent in African-American than in Caucasian patients, and were associated with a significant reduction in OS (8.7 versus 12.9 months; P = 0.008).

CONCLUSION

None of the biomarkers was predictive of treatment response in women with metastatic breast cancer; however, survival differed according to hormone receptor and p53 status. Triple negative tumors were more frequent in African-American patients and were associated with a shorter survival.

Thirteen new p53 gene mutants identified among 41 human breast cancer cell lines

The p53 tumor suppressor gene is frequently mutated in breast cancer. Here, we used direct sequencing to screen the complete coding sequence of the p53 gene from 41 human breast cancer cell lines. We identified 32 cell lines (78%) with a p53 gene alteration that predicted a change in the encoded protein. Thirty-one of these mutations were accompanied by loss of the other p53 allele. All mutations but one were unique and 27 mutations had previously been identified in uncultured human cancers. Ten mutations were predicted to encode a truncated p53 protein and 22 missense mutations were identified. p53 transcript expression was analyzed by semi-quantitative RT-PCR and p53 protein expression was determined by Western blotting. Our analyses revealed three p53 expression patterns: wild-type p53 cell lines had normal transcript levels and low or no detectable protein expression; cell lines with a p53 truncating mutation had low transcript levels and low or no detectable protein expression; and cell lines with a p53 missense mutation had highly variable transcript and protein expression levels. As a whole, our data represent a p53 mutation profile in breast cancer cell lines, providing a model for structural, functional and pharmacological studies on p53 in human cancer.

The efficacy of trastuzumab in Her-2/neu-overexpressing metastatic breast cancer is independent of p53 status

PURPOSE

Her-2/neu and p53-mediated signalling have been shown to interact at various cellular levels. However, the clinical relevance of p53 alterations in patients receiving trastuzumab for Her-2/neu-overexpressing metastatic breast cancer (MBC) remains unknown. The present study was performed to corroborate previous in vitro findings from our laboratory showing that trastuzumab induces growth arrest and apoptosis in a p53-independent manner.

METHOD

Retrospective immunohistochemical (IHC) analysis for p53 protein expression was carried out on tumour specimens from 104 patients receiving trastuzumab-based treatment for Her-2/neu-overexpressing MBC at a single institution. p53 status was correlated with response (R) and clinical benefit (CB), median progression-free survival (PFS) time and overall survival (OAS) time in univariate and multivariate analyses.

RESULTS

Characteristics were similar between p53-negative and p53-positive tumours (all P>0.05). In univariate analyses, R (39% vs 26%, P=0.208), CB (70% vs 57%, P=0.218), PFS (6.2 months vs 4.2 months, P=0.186) and OAS (23.8 months vs 23.2 months, P=0.650) were similar for p53-positive tumours and p53-negative tumours, respectively. In multivariate analyses, p53 status was not a significant predictor of R, CB, PFS or OAS (all P>0.05).

CONCLUSIONS

p53 status, as determined by IHC, is not a predictor of the clinical efficacy of trastuzumab-based treatment in patients with Her-2/neu-overexpressing MBC.

Prognostic Significance of Tumor Suppressor Gene Expression and Mutations in Human Osteosarcoma

Purpose: Various studies examining the relationship between tumor suppressor protein TP53 overexpression and/or TP53 gene mutations and the response to chemotherapy and clinical outcome in patients with osteosarcoma have yielded inconclusive results. The purpose of the current study was to evaluate the relation of TP53 status with response to chemotherapy and/or clinical outcome in osteosarcoma.

Experimental Design: We conducted a meta-analysis of 16 studies (n = 499 patients) that evaluated the correlation between TP53 status and histologic response to chemotherapy and 2-year survival. Data were synthesized in summary receiver operating characteristic curves and with summary likelihood ratios (LRs) and risk ratios.

Results: The quantitative synthesis showed that TP53 status is not a prognostic factor for the response to chemotherapy. The positive LR was 1.21 (95% confidence interval, 0.86–1.71), and the negative LR was 0.91 (95% confidence interval, 0.77–1.07). There was no significant between-study heterogeneity. TP53-positive status tended to be associated with a worse 2-year survival, but the overall results were not formally statistically significant. The association was formally significant in studies that clearly stated that measurements were blinded to outcomes (risk ratio, 2.05; 95% confidence interval, 1.23–3.44), and in studies using reverse transcription-PCR for evaluating TP53 alterations (risk ratio, 1.76; 95% confidence interval, 1.07–2.91).

Conclusions: TP53 status is not associated with the histologic response to chemotherapy in patients with osteosarcoma, whereas TP53 gene alterations may be associated with decreased survival.

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.

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.

Molecular alterations in sporadic breast cancer

Breast cancer is a genetic disease. Like other human cancers, it is thought to occur as the result of progressive accumulation of genetic aberrations. These aberrations result in a deviation of the gene expression profiles from that of the normal progenitor cell. In up to 99% of cases, breast cancer is due to solely somatic genetic aberrations without germ-line ones. Considerable progress have already been made in understanding the genetic mechanisms underlying the development and progression of breast cancer. Several extensively studied genes are now well known to be involved. Unfortunately, our ability to make clinically useful interventions on the basis of these data is limited. Because of the involvement of multiple genes and complex pathways in a single cancer cell, the molecular dysfunctioning underlying breast cancer remains to be completely clarified. In a next future, studying the global gene expression of different types of tumors will allow the development of expression profiles unique for a breast cancer, its stage and prognostic category, leading to diagnostic assays and the identification of new therapeutic targets.

Tumor-specific DNA in plasma of breast cancer patients

The presence of DNA fragments circulating in cancer patients was described a number of years ago. The mere presence of DNA in the circulation is not indicative of cancer. However, there are reports that apoptosis and necrosis of the cancer cells can increase the levels of circulating DNA. The study of plasma DNA with the detection of genetic abnormalities associated with specific cancers has produced some promising results. Primary cancer often harbors ras or p53 mutations and the detection of these mutations in free circulating DNA could indicate the presence of cancer. Other approaches have included detection of specific losses of heterozygosity (LOH), microsatellite instability (MI) and promoter hyper-methylation. For breast cancer, studies published to date have focused on detecting LOH, MI and methylation of the p16INK4A promoter. Good concordance between alterations in the primary tumor and detection of the same alterations in the circulation has been observed. Also, it is encouraging to note that DNA alterations have been detected in patients with small or even in situ lesions, indicating that circulating tumor DNA is shed early in the disease process. If 'universal' breast-specific DNA alterations can be identified, this approach may hold significant promise for early detection of breast cancer.

Enzymatic Mutation Detection Method Evaluated for Detection of p53 Mutations in cDNA from Breast Cancers

Background: Rapid, reproducible, and easily run methods with high sensitivity and specificity are required for mutation screening of clinical samples. We evaluated the Enzymatic Mutation Detection (EMDTM) method by analysis of archival cDNA from 203 breast cancer patients and comparison with results of cDNA-based sequencing of the tumor suppressor gene p53.

Methods: The EMD technology uses the T4 endonuclease VII, which cleaves double-stranded DNA at sites where a DNA mismatch is present because of mispairing or an insertion/deletion of nucleotides. The EMD analyses were carried out by dividing the p53 gene into two overlapping fragments that were analyzed separately. After PCR amplification, the fragments were hybridized with wild-type p53 and subsequently exposed to the EMD enzyme. Cleavage products were analyzed and scored using an ALFTM automated DNA sequencer and ALFwin Fragment Analyzer software (Ver. 1.02).

Results: The EMD technique had sensitivities of 45% and 64% and specificities of 83% and 84% for the two fragments, respectively. Patients with EMD-positive, wild-type p53 tumors had a survival similar to that of patients with EMD-negative, wild-type p53 tumors. Node-positive patients with p53 mutated tumors according to sequencing had a statistically significantly worse overall survival than those with p53 wild-type tumors (P = 0.016), whereas this difference in survival was not detected when p53 status was determined with EMD (P = 0.47).

Conclusions: EMD had insufficient sensitivity for consideration in screening for the p53 gene in this archival material. Sequencing must still be considered as the standard procedure.

Can axillary dissection be avoided by improved molecular biological diagnosis?

Axillary dissection is presently a routine staging procedure in the management of breast cancer. The use of adjuvant systemic treatment is largely based on the diagnosis of axillary metastases. Routine axillary dissection leads to acute and chronic side-effects in a large proportion of patients. The sentinel node technique is presently explored with the aim of decreasing the need for standard axillary dissection. A complementary way forward is to analyse the primary breast cancer for molecular markers with prognostic significance with reference to the risk for metastatic capacity and thereby obtain a 'biological staging' and identify those patients in need of systemic adjuvant therapy. A large number of molecular biological factors have been shown to have prognostic significance in breast cancer e.g. c-erbB-2, p53, uPA, PAI-I and VEGF. This article reviews the expression of these and other factors in the primary breast cancers in relation to the risk for axillary and systemic metastatic disease, with the long-term aim of excluding routine axillary dissection.

Improving the detection of p53 mutations in breast cancer by use of the FASAY, a functional assay

The aim of this investigation was to examine the ability of the yeast-based functional assay, the functional analysis for the separation of alleles in yeast (FASAY), to detect p53 mutations in breast cancers when compared with immunohistochemistry and automated sequencing of the whole p53 gene (exons 1-11). To achieve this, all three methods were carried out on a cohort of aggressive breast tumors. In those tumors, in which the FASAY analysis indicated the presence of a mutation, cDNA was extracted from red yeast colonies and was sequenced to identify the base change in the p53 gene. The FASAY detected all 24 mutations found in the series of 48 tumors, whereas initial automated sequencing of genomic DNA detected 18/24 mutations. A second round of automated sequencing carried out using an independent source of genomic DNA detected mutations in 3 of the 6 tumors that originally appeared to lack a mutation in genomic DNA. All but 1 of the mutations originally missed by sequencing of genomic DNA were point mutations. Five mutations in this series (21%) were outside the commonly investigated exons 5-8, reinforcing the need to extend sequencing beyond this region. Of 24 tumors, 14 had strong immunohistochemical staining, and all 14 had p53 mutations; the majority of mutations missed by immunohistochemistry produced a truncated protein. Strong staining was not seen in tumors lacking a p53 mutation. The FASAY proved to be a rapid, reliable, and effective method for identifying those breast tumors harboring p53 mutations.

p53 website and analysis of p53 gene mutations in human cancer: forging a link between epidemiology and carcinogenesis

The p53 tumor suppressor gene has proven to be one of the genes most often mutated in human cancers. It involves mainly point mutations leading to amino acid substitutions in the central region of the protein which impairs normal functions. Analysis of the mutational events that target the p53 gene has revealed evidence for both exogenous and endogenous mutational mechanisms. For example, the p53 mutational spectrum reveals evidence for a direct causal effect of ultraviolet radiation in skin cancer, of aflatoxin B1 in liver cancer, and of tobacco smoke in lung cancer. This novel field, molecular epidemiology of human cancer risk, has added a new dimension to classical associative epidemiology by providing a direct link between human cancer and carcinogen exposure. For such analysis, we devised a generic software called UMD (Universal Mutation Database). It was developed as a generic software to create locus-specific databases (LSDBs) with the 4(th) Dimension(R) package from ACI. This software includes an optimized structure to assist and secure data entry and to allow the input of various clinical data.

Somatic mutations in the p53 gene and prognosis in breast cancer: a meta-analysis

Many studies have investigated the association between alterations in the p53 gene and clinical outcome of breast cancer, and most investigators have reported poorer overall and disease-free survival (as indicated by a relative hazard (RH) greater than one) in breast cancer cases with somatic mutations in p53. However, different studies have produced widely differing RH estimates, ranging from no risk (RH = 1) to a relative hazard of 23, and not all of these results have been statistically significant. We have therefore reviewed all the published studies that have investigated the association between somatic mutations in the p53 gene and breast cancer prognosis and used standard techniques of meta-analysis to combine the results of these studies to produce a more precise estimate of the prognostic significance of p53 mutations. Eleven studies investigated overall survival in a total of 2319 unselected cases. The RH estimates from these ranged from 1 to 23.4 with a combined RH estimate of 2.0 (confidence interval 1.7-2.5). Three studies investigated the role of p53 in node-negative patients and in these, the combined estimate of RH was 1.7 (1.2-2.3). For three studies of node-positive breast cancer the combined risk estimate was 2.6 (1.7-3.9). The inclusion of p53 mutation screening in large breast cancer clinical trials seems warranted in the light of these results. Analysis of large numbers of cases matched for stage and therapy will allow definitive clarification of the value of p53 mutational status in prognostication, and possibly choice of therapy.

Drug-induced apoptosis and p53, BCL-2 and BAX expression in breast cancer tissues in vivo and in fibroblast cells in vitro

BACKGROUND

Chemotherapeutic management of breast cancers is a difficult task as they show significant differences in chemosensitivity. The present study was undertaken to determine the usefulness of the apoptosis-related factors as indicators of tumor sensitivity to 5'-deoxyfluorouridine (5'-DFUR) in breast cancers.

METHODS

(1) Forty-six breast cancer patients were randomly assigned to a group in which oral 5'-DFUR (1200 mg/day) was administered for more than 5 days before operation (24 patients) and a control group who received no preoperative chemotherapy (22 patients). Surgical specimens were examined for the frequency of apoptotic cells [apoptotic index (AI)] by a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling method and for the expression of p53, BCL-2 and BAX by immunohistochemical staining. (2) Normal human diploid fetal lung fibroblast, IMR90 and SV40 transformed IMR90 were exposed to 5-FU. Apoptotic cells were detected by flow cytometry and BCL-2 and BAX mRNAs by real-time quantitative RT-PCR analysis.

RESULTS

(1) No significant difference in the AIs or in BCL-2 and BAX scores was observed between the 5'-DFUR-treated and control groups. However, in the p53 negative subgroup (n = 36), AI and BAX scores were higher and BCL-2 scores lower in the 5'-DFUR group than in the control group (P = 0.006, 0.008 and 0.050, respectively). (2) The sensitivity of IMR90 was significantly decreased by SV40 transformation and the 5-FU-induced cytotoxicity was mainly due to induction of apoptosis. The BCL-2/BAX mRNA ratio was decreased in response to 5-FU in IMR90. These results correlated with our clinical data.

CONCLUSIONS

Preoperative treatment with 5'-DFUR induced apoptosis and changes in BCL-2 and BAX expression in p53 negative breast cancers. p53 status, AI and the BCL-2/BAX ratio may be useful information for the choice of postoperative chemotherapy for breast cancer.