Association between basal-like phenotype and BRCA1/2 germline mutations in Korean breast cancer patients

INTRODUCTION

BRCA mutation testing allows index patients and their families to be provided with appropriate cancer risk-reduction strategies. Because of the low prevalence of BRCA mutations in unselected breast cancer patients and the high cost of genetic testing, it is important to identify the subset of women who are likely to carry BRCA mutations. In the present study, we examined the association between BRCA1/2 germline mutations and the immunohistochemical features of breast cancer.

METHODS

In a retrospective review of 498 breast cancer patients who had undergone BRCA testing at Seoul National University Bundang Hospital between July 2003 and September 2012, we gathered immunohistochemical information on estrogen receptor (er), progesterone receptor (pr), her2 (human epidermal growth factor receptor 2), cytokeratin 5/6, egfr (epidermal growth factor receptor), and p53 status.

RESULTS

Among the 411 patients eligible for the study, 50 (12.2%) had germline mutations in BRCA1 or BRCA2. Of the 93 patients with triple-negative breast cancer (tnbc), 25 with BRCA1/2 mutations were identified (BRCA1, 20.4%; BRCA2, 6.5%). On univariate analysis, er, pr, cytokeratin 5/6, egfr, and tnbc were found to be related to BRCA1 mutations, but on multivariate analysis, only tnbc was significantly associated with BRCA1 mutations. Among patients with early-onset breast cancer or with a family history of breast or ovarian cancer, BRCA1 mutations were significantly more prevalent in the tnbc group than in the non-tnbc group.

CONCLUSIONS

In the present study, tnbc was the only independent predictor of BRCA1 mutation in patients at high risk of hereditary breast and ovarian cancers. Other histologic features of basal-like breast cancer did not improve the estimate of BRCA1 mutation risk.

Prognostic value of tumor-infiltrating lymphocytes in Epstein-Barr virus-associated gastric cancer

BACKGROUND

This study explored the prognostic impact of tumor-infiltrating lymphocytes (TILs) and investigated whether three histologic subtypes (lymphoepithelioma-like carcinoma, carcinoma with Crohn's disease-like lymphoid reaction, and conventional-type adenocarcinoma) could stratify a prognostic subset for patients with Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC).

MATERIALS AND METHODS

After reviewing 1318 consecutive cases of surgically resected or endoscopic submucosal dissected gastric cancers, 120 patients were identified as EBV-positive using EBV-encoded RNA in situ hybridization. The evaluation of the percentage of intratumoral (iTu-) and stromal (str-) TILs was carried out, and the cases were also subclassified into three histologic subtypes as noted above.

RESULTS

Among the 120 patients, 73 patients (60.8%) and 60 patients (50.0%) were determined as str-TIL-positive and iTu-TIL-positive, respectively. In a univariate analysis, str-TIL-positivity was significantly associated with longer recurrence-free survival (RFS; P = 0.002) and disease-free survival (DFS; P = 0.008), yet not overall survival (OS; P = 0.145). While iTu-TIL-positivity has a tendency of favorable outcome indicator for DFS and OS, but statistically significant differences were not shown, respectively (RFS, P = 0.058; DFS, P = 0.151; OS, P = 0.191). In a multivariate analysis using a Cox proportional hazard model adjusted for age, pTNM stage, lymphatic invasion, perineural invasion, and venous invasion; histologic subtype, WHO classification, and str-TIL-positivity were independently or tentatively associated with favorable RFS (hazard ratio [HR] = 12.193, 95% confidence interval [95% CI] 1.039-143.055, P = 0.047) or DFS (HR = 4.836, 95% CI 0.917-25.525, P = 0.063).

CONCLUSION

The histologic subclassification and TILs can be used to predict RFS and DFS for patients with EBVaGC.

Prognostic and predictive values of EGFR overexpression and EGFR copy number alteration in HER2-positive breast cancer

Background:

Epidermal growth factor receptor (EGFR) is overexpressed in a subset of human epidermal growth factor receptor 2 (HER2)-positive breast cancers, and coexpression of HER2 and EGFR has been reported to be associated with poor clinical outcome. Moreover, interaction between HER2 and EGFR has been suggested to be a possible basis for trastuzumab resistance.

Methods:

We analysed the clinical significance of EGFR overexpression and EGFR gene copy number alterations in 242 HER2-positive primary breast cancers. In addition, we examined the correlations between EGFR overexpression, trastuzumab response and clinical outcome in 447 primary, and 112 metastatic HER2-positive breast cancer patients treated by trastuzumab.

Results:

Of the 242 primary cases, the level of EGFR overexpression was 2+ in 12.7% and 3+ in 11.8%. High EGFR gene copy number was detected in 10.3%. Epidermal growth factor receptor overexpression was associated with hormone receptor negativity and high Ki-67 proliferation index. In survival analyses, EGFR overexpression, but not high EGFR copy number, was associated with poor disease-free survival in all patients, and in the subgroup not receiving adjuvant trastuzumab. In 447 HER2-positive primary breast cancer patients treated with adjuvant trastuzumab, EGFR overexpression was also an independent poor prognostic factor. However, EGFR overexpression was not associated with trastuzumab response, progression-free survival or overall survival in the metastatic setting.

Conclusions:

Epidermal growth factor receptor overexpression, but not high EGFR copy number, is a poor prognostic factor in HER2-positive primary breast cancer. Epidermal growth factor receptor overexpression is a predictive factor for trastuzumab response in HER2-positive primary breast cancer, but not in metastatic breast cancer.

Clinicopathologic and prognostic significance of c-MYC copy number gain in lung adenocarcinomas

BACKGROUND

c-MYC copy number gain (c-MYC gain) has been associated with aggressive behaviour in several cancers. However, the role of c-MYC gain has not yet been determined in lung adenocarcinomas classified by genetic alterations in epidermal growth factor receptor (EGFR), KRAS, and anaplastic lymphoma kinase (ALK) genes. We investigated the clinicopathologic and prognostic significance of c-MYC gain for disease-free survival (DFS) and overall survival (OS) according to EGFR, KRAS, and ALK gene status and stages in lung adenocarcinomas.

METHODS

In 255 adenocarcinomas resected in Seoul National University Bundang Hospital from 2003 to 2009, fluorescence in situ hybridisation (FISH) with c-MYC probe and centromeric enumeration probe 8 (CEP8) was analysed using tissue microarray containing single representative core per each case. EGFR (codon 18 to 21) and KRAS (codon 12, 13, and 61) mutations were analysed by polymerase chain reaction and direct sequencing method from formalin-fixed, paraffin-embedded tissue sections. ALK rearrangement was determined by FISH method. c-MYC gain was defined as >2 copies per nucleus, chromosome 8 gain as ⩾3 copies per nucleus, and gain of c-MYC:CEP8 ratio (hereafter, c-MYC amplification) as ⩾2.

RESULTS

We observed c-MYC gain in 20% (51 out of 255), chromosome 8 gain in 5.5% (14 out of 255), c-MYC amplification in 2.4% (6 out of 255), EGFR mutation in 49.4% (118 out of 239), KRAS mutation in 5.7% (7 out of 123), and ALK rearrangement in 4.9% (10 out of 205) of lung adenocarcinomas. c-MYC gain was observed in 19% (22 out of 118) of patients with lung adenocarcinomas with an EGFR mutation, but not in any patients with a KRAS mutation, or an ALK rearrangement. c-MYC gain (but not chromosome 8 gain or c-MYC amplification) was an independent poor-prognostic factor in the full cohort of lung adenocarcinoma (P=0.022, hazard ratio (HR)=1.71, 95% confidence interval (CI), 1.08-2.69 for DFS; P=0.032, HR=2.04, 95% CI, 1.06-3.91 for OS), as well as in stage I subgroup (P=0.023, HR=4.70, 95% CI, 1.24-17.78 for DFS; P=0.031, HR=4.65, 95% CI, 1.15-18.81 for OS), and in EGFR-mutant subgroup (P=0.022; HR=2.14; 95% CI, 1.11-4.10 for DFS).

CONCLUSIONS

c-MYC gain (but not chromosome 8 gain or c-MYC amplification) was an independent poor-prognostic factor for DFS and OS in lung adenocarcinomas, both in full cohort and stage I cancer, and possibly for DFS in EGFR-mutant adenocarcinomas. Additional studies are required to determine if patients with lung adenocarcinoma with c-MYC gain are candidates for additional first-line treatment to mitigate their increased risk for disease progression and death.

Abstract P1-08-39: Tumor-infiltrating CD8+ lymphocytes as an independent predictive factor for pathologic complete response to primary systemic therapy in breast cancer

Background: Tumor infiltrating lymphocytes (TILs), stem cell phenotype and epithelial-mesenchymal transition (EMT) are known to be associated with response to primary systemic therapy (PST) in breast cancer. However, these markers are strongly correlated with triple negative breast cancer, which shows high pathologic complete response (pCR) to PST. This study was conducted to evaluate clinical implication of these markers as predictive factor for pCR after PST in breast cancer and to find independent predictive factors, irrespective of breast cancer subtype.

Methods: The pre-chemotherapeutic biopsy specimens of 153 breast cancer patients who underwent surgical resection after anthracycline-or anthracycline/taxane-based PST were enrolled. TILs (CD4, CD8, and FOXP3), breast cancer stem cell phenotype (CD44+/CD24-, and ALDH1), expression of EMT markers [vimentin, smooth muscle actin (SMA), osteonectin, E-cadherin, and N-cadherin] were evaluated by immunohistochemistry and were correlated with pCR after PST.

Results: High infiltration of TILs (CD4+, CD8+, and FOXP3+), expression of stem cell markers (CD44+/CD24-, ALDH1+) and expression of EMT markers (expression of vimentin, SMA and osteonectin; loss of E-cadherin) were significantly associated with high histologic grade and triple negative breast cancer. Of them, high TILs (CD4+, CD8+, and FOXP3+) and expression of ALDH1, vimentin and osteonectin were associated with pCR. In multivariate analysis, CD8+ TILs and a conventional predictive marker, Ki67 were found to be independent predictors for pCR. In subgroup analyses, high CD8+ TILs was remained as a predictive factor for pCR, irrespective of PST regimen and tumor subtype.

Conclusion: CD8+ TILs could therefore be used as a reliable predictor of response to PST in breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-39.

Abstract P1-08-38: HER2 heterogeneity affects trastuzumab responses and survival in patients with HER2-postive metastatic breast cancer

Purpose: Heterogeneity of HER2 gene amplification is found in a subset of breast cancers. However, it is not known whether breast cancers with heterogeneous HER2 amplification respond differently to HER2-targeted therapy than those with homogeneous amplification. In this study, we investigated the relationship between HER2 heterogeneity and trastuzumab resistance and clinical outcomes in patients with HER2-positive metastatic breast cancer.

Patients and methods: We studied tumor tissues from 127 patients with HER2-positive metastatic breast cancers who had received trastuzumab-based chemotherapy. Regional and genetic heterogeneity of HER2 amplification was determined in three different areas of each tumor by immunohistochemistry (IHC) and silver in situ hybridization. We also assessed the overall levels of HER2 amplification, and the proportion of tumor cells with a HER2/CEP17 ratio >2.2 or HER2 overexpression (IHC score of 3+). HER2status including HER2 heterogeneity was correlated with trastuzumab responses and survival of the patients.

Results: HER2regional and genetic heterogeneity was confirmed in 7.8% and 3.6% of cases, respectively. Poor response to trastuzumab was associated with overall low-level amplification, HER2regional heterogeneity, HER2/CEP17 ratio >2.2 in <80% of tumor cells, and HER2 IHC score of 3+ in <75% of tumor cells. In survival analyses, low-level HER2 amplification, HER2regional heterogeneity, and HER2/CEP17 ratio >2.2 in <80% of tumor cells were associated with shorter time to progression and lower overall survival in univariate and multivariate analyses.

Conclusion: Accurate assessment of HER2 status including HER2 heterogeneity is important in predicting trastuzumab responses and outcomes in patients with HER2-positive metastatic breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-38.

Tumour-infiltrating CD8+ lymphocytes as an independent predictive factor for pathological complete response to primary systemic therapy in breast cancer

Background:

Tumour-infiltrating lymphocytes (TILs) are known to be associated with response to primary systemic therapy (PST) in breast cancer. This study was conducted to assess the association of TIL subsets with pathological complete response (pCR) after PST in breast cancer in relation to breast cancer subtype, breast cancer stem cell (BCSC) phenotype and epithelial–mesenchymal transition (EMT).

Methods:

The pre-chemotherapeutic biopsy specimens of 153 breast cancer patients who underwent surgical resection after anthracycline- or anthracycline/taxane-based PST were analysed. TIL subsets (CD4+, CD8+, and FOXP3+ TILs), BCSC phenotype, and the expression of EMT markers were evaluated by immunohistochemistry and were correlated with pCR after PST.

Results:

Infiltration of CD4+ and CD8+ T lymphocytes was closely correlated with BCSC phenotype and EMT. High levels of CD4+, CD8+, and FOXP3+ TILs were associated with pCR, and CD8+ TILs were found to be an independent predictive factor for pCR. In addition, CD8+ TILs were associated with pCR irrespective of breast cancer subtype, CD44+/CD24− phenotype, EMT, and chemotherapeutic regimen in subgroup analyses.

Conclusion:

These findings indicate that CD8+ cytotoxic T lymphocytes are a key component of TILs associated with chemo-response and can be used as a reliable predictor of response to anthracycline- or anthracycline/taxane-based PST in breast cancer.