Possible difference in frequencies of genetic polymorphisms of estrogen receptor alpha, estrogen metabolism and P53 genes between estrogen receptor-positive and -negative breast cancers.

OBJECTIVE: Genetic polymorphisms associated with breast cancer risk are likely to differ among ethnic and molecular subtypes. The ability to identify genetic polymorphisms affecting the risk of estrogen receptor (ER)-positive breast cancer may lead to the more efficient selection of candidates for chemoprevention with endocrine agents. We focused on identifying common genotypes for ER-positive breast cancer in premenopausal Japanese women. METHODS: We compared genetic polymorphisms of ERalpha, estrogen metabolism genes (CYP17A1, CYP19A1, HSD17B1 COASY, CYP1B1 and COMT), and p53 between ER-positive and -negative female Japanese breast cancer patients, and analyzed whether these polymorphisms affected the frequency of ER-positive breast cancer. RESULTS: Carriers of the G allele of ERalpha (rs6905370) were more frequent in ER-positive breast cancer than in ER-negative breast cancer especially in those under 50-year old. Pairwise analysis showed that combinations of the ERalpha G allele with the homozygous Trp genotype of CYP19A1 codon 39 (rs2236722), the methionine (Met) allele of COMT codon 158 (rs4680) or Pro allele of p53 codon 72 (rs1042522) were more frequent in ER-positive than ER-negative breast cancer, especially in patients less than 50-year old. The frequencies of these combinations were even higher in patients with strongly ER-positive tumors (Allred's scores of 7 or 8). CONCLUSION: Our study demonstrated genetic polymorphisms of ERalpha, CYP19A1, COMT and p53 genes frequently occur in ER-positive breast cancer in premenopausal Japanese women.

Low phosphorylation of estrogen receptor alpha (ERalpha) serine 118 and high phosphorylation of ERalpha serine 167 improve survival in ER-positive breast cancer.

Endocrine therapy has become the most important treatment option for women with estrogen receptor (ER)-positive breast cancer. Urgently needed are prognostic assays that can identify those who need additional adjuvant therapy, such as signal transduction inhibitors or chemotherapy, for ER-positive early breast cancer. We examined phosphorylation of ERalpha serine (Ser) 118, ERalpha Ser167, p44/42 mitogen-activated protein kinase (MAPK), and Akt and expression of progesterone receptor, amplified in breast cancer 1 (AIB1), human epidermal growth factor receptor 2 (HER2), p53, and Ki67 in ER-positive breast cancers by immunohistochemistry, and analyzed their significance for prognosis. Phosphorylation levels of ERalpha Ser118, ERalpha Ser167, MAPK, and Akt were positively correlated. AIB1 expression was significantly associated with phosphorylation of ERalpha Ser118, MAPK, and Akt, and HER2 expression. Low phosphorylation of ERalpha Ser118 and high phosphorylation of ERalpha Ser167 were associated with significantly improved disease-free (P=0.0003 and P=0.0002 respectively) and overall survival (P=0.0007 and P=0.0016 respectively) in multivariate analyses. Our data suggest that phosphorylation of ERalpha Ser118 and ERalpha Ser167 affects survival in ER-positive breast cancer and could be helpful in distinguishing patients who are likely to benefit from endocrine therapy alone from those who are not.

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.

p53 protein accumulation predicts resistance to endocrine therapy and decreased post-relapse survival in metastatic breast cancer.

INTRODUCTION: Endocrine therapy is the most important treatment option for women with hormone receptor-positive breast cancer. The potential mechanisms for endocrine resistance involve estrogen receptor (ER)-coregulatory proteins and cross-talk between ER and other growth factor-signaling networks. However, the factors and pathways responsible for endocrine resistance are still poorly identified. MATERIALS AND METHODS: The expression of HER2, p53, and Ki67 was examined by immunohistochemistry in primary breast tumour specimens from 73 metastatic breast cancer patients who received first-line treatment with endocrine therapy on relapse, and analysed to determine whether expression of these molecular markers affected the response to endocrine therapy. RESULTS: Of the 73 invasive ductal carcinomas, 12.3%, 21.9%, and 35.6% were positive for HER2 overexpression, p53 protein accumulation, and Ki67 expression, respectively. All patients received endocrine therapy as first-line treatment for metastatic breast cancer; 34 patients (46.6%) responded. Patients with primary breast tumours that had p53 protein accumulation and Ki67 expression showed significantly more resistance to endocrine therapy (P = 0.0049 and P = 0.024, respectively). There were also tendencies for HER2 overexpression to correlate with resistance to endocrine therapy, but this did not reach significance. p53 protein accumulation and HER2 overexpression significantly reduced post-relapse survival (P < 0.0001 and P = 0.001, respectively), and these factors were also statistically significant in a multivariate analysis. CONCLUSION: These data suggest that p53 protein accumulation is helpful in selecting patients who may benefit from endocrine therapy and is a prognostic marker in hormone receptor-positive metastatic breast cancer.

Immunohistochemical evaluation of hormone receptor status for predicting response to endocrine therapy in metastatic breast cancer.

BACKGROUND: The importance of establishing hormone receptor status of tumors for the treatment of women with hormone receptor-positive breast cancer has been emphasized, however, there is no general agreement as to how immunohistochemical assays should be evaluated. It is critical to evaluate hormone receptor status when considering response to endocrine therapy. METHODS: Estrogen receptor (ER) and progesterone receptor (PgR) expression was examined by immunohistochemistry using Allred's score for primary breast tumors from 75 metastatic breast cancer patients who received first-line treatment with endocrine therapy (56 patients received tamoxifen, 11 patients received aromatase inhibitors, and 8 patients received LH-RH agonist or other endocrine reagents) on relapse. Correlation between hormone receptor status and response to endocrine therapy as well as post-relapse survival was analyzed. RESULTS: The most significant correlation between positive ER expression and response to any endocrine therapy (p = 0.011) or tamoxifen only (p = 0.030) occurred when the cutoff score was set at 10%. When the evaluation was based on Allred's score (TS), a cutoff point of TS>or=4 showed a more significant association between positive ER expression and response to all kinds of endocrine therapy (p = 0.020) or tamoxifen only (p = 0.047). When evaluated at a cutoff point of 1% positive cells, there were fifteen patients with both ER- and PgR-negative tumors, and three patients (20.0%) responded to the therapy. Patients with 1% or more ER or PgR positive cells had better survival after relapse (p = 0.0005 and p = 0.0008, respectively). CONCLUSIONS: The proportion score alone might be enough to predict hormone responsiveness and post-relapse survival in metastatic breast cancer. The cutoff might be set low, for example 1%, especially for metastatic disease.

Phosphorylation of estrogen receptor alpha serine 167 is predictive of response to endocrine therapy and increases postrelapse survival in metastatic breast cancer.

INTRODUCTION: Endocrine therapy is the most important treatment option for women with hormone-receptor-positive breast cancer. The potential mechanisms for endocrine resistance involve estrogen receptor (ER)-coregulatory proteins and crosstalk between ER and other growth factor signaling networks. However, the factors and pathways responsible for endocrine resistance are still poorly identified. METHODS: Using immunohistochemical techniques, we focused on the expression and phosphorylation of hormone receptors themselves and examined the phosphorylation of ER-alpha Ser118 and ER-alpha Ser167 and the expression of ER-alpha, ER-beta1, ER-betacx/beta2, progesterone receptor (PR), PRA, and PRB in the primary breast carcinomas of 75 patients with metastatic breast cancer who received first-line treatment with endocrine therapy after relapse. RESULTS: Phosphorylation of ER-alpha Ser118, but not Ser167, was positively associated with overexpression of HER2, and HER2-positive tumors showed resistance to endocrine therapy. The present study has shown for the first time that phosphorylation of ER-alpha Ser167, but not Ser118, and expression of PRA and PRB, as well as ER-alpha and PR in primary breast tumors are predictive of response to endocrine therapy, whereas expression of ER-beta1 and ER-betacx/beta2 did not affect response to the therapy. In addition, patients with either high phosphorylation of ER-alpha Ser167, or high expression of ER-alpha, PR, PRA, or PRB had a significantly longer survival after relapse. CONCLUSION: These data suggest that phosphorylation of ER-alpha Ser167 is helpful in selecting patients who may benefit from endocrine therapy and is a prognostic marker in metastatic breast cancer.

Dominant-negative Stat5 inhibits growth and induces apoptosis in T47D-derived tumors in nude mice.

Signal transducer and activator of transcription 5 (Stat5) regulates growth, differentiation, and survival of mammary and hematopoietic cells. The role of Stat5 in breast cancer has not been established, although Stat5 is critical for some hematopoietic malignancies. In this study, we have analyzed the role of Stat5 in progression of the estrogen receptor-positive T47D human breast cancer cell line, in which Stat5b is constitutively activated. Expression of Stat5-regulated genes, such as cyclin D1 and bcl-xL, was strongly suppressed in T47D cells infected with the dominant-negative Stat5 adenovirus, AdStat5aDelta740. We also determined the phenotypic effects of introduction of dominant-negative Stat5 on T47D-derived tumors in nude mice. Tumors injected with AdStat5aDelta740 showed a 60% reduction in size, which was associated with the induction of apoptosis. Our results indicate the possibility of using dominant-negative Stat5 to induce apoptosis in certain Stat5-activated breast cancers.

Coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer.

INTRODUCTION: Many laboratories are currently evaluating the usefulness of determination of HER2, p53, and Ki67 proliferation indices using immunohistochemical techniques in cancer. Although the available studies suggest that these factors might indeed be helpful in making treatment decisions in cancer patients, their clinical usefulness is still controversial. METHODS: Expression of HER2, p53, and Ki67 was examined by immunohistochemistry in samples of breast tissue from 506 patients with invasive ductal carcinoma, obtained between 1981 and 1999 (median follow up period 82 months), and their significance for prognosis was analyzed. RESULTS: Of the 506 carcinoma tissue samples, 20.1%, 29.0%, and 53.6% were positive for HER2 over-expression, p53 protein accumulation, and Ki67 expression, respectively. Over-expression of HER2 significantly reduced disease free (P = 0.02) and overall survival (P = 0.005). Accumulation of p53 protein significantly decreased disease free (P = 0.01) and overall survival (P = 0.01). Patients with tumors that were positive for both HER2 and p53 relapsed and died within a significantly shorter period of time after surgery (P = 0.0001 and P < 0.0001, respectively). In multivariate analysis, patients with both HER2 and p53 positive tumors had considerably decreased overall survival (P = 0.04), as did patients with larger tumor size and positive lymph node status. CONCLUSION: The findings of the present study indicate that the coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer.