Robert S. Seitz

Mammostrat as a tool to stratify breast cancer patients at risk of recurrence during endocrine therapy.

IntroductionPatients with early-stage breast cancer, treated with endocrine therapy, have approximately 90% 5-year disease-free survival. However, for patients at higher risk of relapse despite endocrine therapy, additional adjuvant therapy, such as chemotherapy, may be indicated. The challenge is to prospectively identify such patients. The Mammostrat® test uses five immunohistochemical markers to stratify patients on tamoxifen therapy into risk groups to inform treatment decisions. We tested the efficacy of this panel in a mixed population of cases treated in a single center with breast-conserving surgery and long-term follow-up.MethodsTissue microarrays from a consecutive series (1981 to 1998) of 1,812 women managed by wide local excision and postoperative radiotherapy were collected following appropriate ethical review. Of 1,390 cases stained, 197 received no adjuvant hormonal or chemotherapy, 1,044 received tamoxifen only, and 149 received a combination of hormonal therapy and chemotherapy. Median age at diagnosis was 57, 71% were postmenopausal, 23.9% were node-positive and median tumor size was 1.5 cm. Samples were stained using triplicate 0.6 mm2 tissue microarray cores, and positivity for p53, HTF9C, CEACAM5, NDRG1 and SLC7A5 was assessed. Each case was assigned a Mammostrat® risk score, and distant recurrence-free survival (DRFS), relapse-free survival (RFS) and overall survival (OS) were analyzed by marker positivity and risk score.ResultsIncreased Mammostrat® scores were significantly associated with reduced DRFS, RFS and OS in estrogen receptor (ER)-positive breast cancer (P < 0.00001). In multivariate analyses the risk score was independent of conventional risk factors for DRFS, RFS and OS (P < 0.05). In node-negative, tamoxifen-treated patients, 10-year recurrence rates were 7.6 ± 1.5% in the low-risk group versus 20.0 ± 4.4% in the high-risk group. Further, exploratory analyses revealed associations with outcome in both ER-negative and untreated patients.ConclusionsThis is the fifth independent study providing evidence that Mammostrat® can act as an independent prognostic tool for ER-positive, tamoxifen-treated breast cancer. In addition, this study revealed for the first time a possible association with outcome regardless of node status and ER-negative tumors. When viewed in the context of previous results, these data provide further support for this antibody panel as an aid to patient management in early-stage breast cancer.

Chemosensitivity and stratification by a five monoclonal antibody immunohistochemistry test in the NSABP B14 and B20 trials.

Purpose: To test the association between risk stratification and outcome in a prospectively designed, blinded retrospective study using tissue arrays of available paraffin blocks from the estrogen receptor–expressing, node-negative samples from the National Surgical Adjuvant Breast and Bowel Project B14 and B20 tamoxifen and chemotherapy trials. Experimental Design: Tissue arrays were stained by immunohistochemistry targeting p53, NDRG1, SLC7A5, CEACAM5, and HTF9C. Risk stratification was done using predefined scoring rules, algorithm for combining scores, and cutoff points for low-risk, moderate-risk, and high-risk patient strata. Results: In a univariate Cox model, this test was significantly associated with recurrence-free interval [HR, 1.3 (95% confidence interval, 1.1-1.6); P = 0.006]. In a multivariate model it contributed information independent of age, tumor size, and menopausal status (P = 0.007). The Kaplan-Meier estimates of the proportion of recurrence-free after 10 years were 73%, 86%, and 85% for the high-risk, moderate-risk, and low-risk groups (P = 0.001). The Kaplan-Meier estimates of the breast-cancer-specific-death rate were 23%, 10%, and 9% (P < 0.0001). Exploratory analysis in patients ≥60 years old showed Kaplan-Meier estimates of the proportion of recurrence-free of 78%, 89%, and 92%. Both high-risk and low-risk groups showed significant improvement on treatment with cytotoxic chemotherapy. Conclusions: Immunohistochemistry using five monoclonal antibodies assigns breast cancer patients to a risk index that was significantly associated with clinical outcome among the estrogen receptor–expressing, node-negative tamoxifen-treated patients. It seems that the test may be able to identify patients who have greater absolute benefit from adjuvant chemotherapy compared with unstratified patient populations. Exploratory analysis suggests that this test will be most useful in clinical decision making for postmenopausal patients.

A search for reliable molecular markers of prognosis in prostate cancer: a study of 240 cases.

Most prostate cancers are treated, although more than 80% remain clinically insignificant and fewer than 3% are fatal. This retrospective study of 240 radical prostatectomy cases with comprehensive follow-up was a search for reliable markers of prostate cancer prognosis evaluable on biopsy specimens to enable minimization of unnecessary treatment, morbidity, and costs. Representative cancer and benign tissue from each prostatectomy specimen was made into tissue microarrays and stained with antibodies targeting 20 gene sequences. Traditional clinical and pathologic prognosticators and the 20 antibody stains were correlated with patient outcomes. By univariable analysis 4 of 20 antibodies (STMN1/stathmin 1, CYP4Z1/cytochrome p450-4z1, CDH1/E-cadherin, and Hey2), Gleason score, perineural invasion, and apical involvement were statistically significant outcome predictors for biopsy tissue. By multivariate analysis, Gleason score, Hey2, and CYP4Z1 were independently predictive. STMN1 and CDH1 were not independent of Gleason score but remain useful because marker interpretation is objective and Gleason scores often differ for biopsy and prostatectomy specimens.

Angiosarcoma: a study of 98 cases with immunohistochemical evaluation of TLE3, a recently described marker of potential taxane responsiveness

Angiosarcomas may be primary in the skin, primary in soft tissue or viscera, or secondary to irradiation. All angiosarcomas have a poor prognosis. Taxanes may have efficacy in the treatment of angiosarcoma. Expression of TLE3 has been associated with improved outcome in taxane‐treated breast cancers. We studied a series of angiosarcoma with TLE3 immunohistochemistry. Cases of angiosarcoma (98 total cases; 37 cutaneous, 48 soft tissue/visceral and 13 post‐irradiation) were retrieved and follow up was obtained. Tumors were classified as ‘vasoformative’, ‘spindled’, ‘epithelioid’ and ‘mixed’. TLE3 immunohistochemistry was performed. Statistical analyses were performed. Patients (50 males and 48 females) had a median age of 60.2 years. Tumors had a median size 7.5 cm and were vasoformative (N = 43, 44%), spindled (N = 21, 21%), epithelioid (N = 16, 16%) and mixed (N = 18, 18%). Follow up was available for 89/98 patients (91%): 32 (36%) were dead due to disease, 36 (41%) were dead due to other causes and 21 (24%) remained alive. The median time to death was 2.1 years. TLE3 reactivity was observed in 0/37 (0%) cutaneous angiosarcomas, in 28/48 (58%) cases from soft tissue/viscera and in 4/13 (31%) post‐irradiation angiosarcomas. (p = <0.0001). Improved 5‐year survival was seen in vasoformative angiosarcomas (p = 0.03). TLE3 expression was not associated with taxane response. However, only a subset of patients was treated with taxane. Our study confirms the poor prognosis of angiosarcoma. Vasoformative angiosarcoma may have a more favorable prognosis. A lack of TLE3 expression in cutaneous angiosarcoma may reflect differing pathogenesis.

Tools to Study the Function of the Ras-Related, Estrogen-Regulated Growth Inhibitor in Breast Cancer

The Ras-related, estrogen-regulated growth inhibitor (Rerg) is a Ras-related small GTPase and candidate tumor suppressor. Rerg gene expression is stimulated by the estrogen receptor alpha (ERalpha), and Rerg gene expression is absent in ER-negative breast cancers. ER-negative breast cancers are highly invasive and metastastic and are typically more advanced than their ER-positive counterparts. Like Ras, Rerg binds and hydrolyzes GTP, but unlike Ras, Rerg has been shown to possess growth inhibitory activity in breast cancer cells. The precise role that Rerg loss plays in breast cancer growth and the mechanisms by which it does so are unknown. This chapter describes tools used to detect and manipulate the expression of Rerg in breast cancer cells. We validate use of an antibody to detect Rerg expression. We describe the generation of expression vectors that encode wild-type and mutants of Rerg that are altered in GDP/GTP regulation. We also describe the development of an inducible Rerg expression system and of a retrovirus-based RNA interference approach to repress Rerg expression. These tools will be invaluable in evaluating the biological function of Rerg in breast cancer.

Mammostrat® as a tool to stratify patients at risk of recurrence during endocrine therapy.

Abstract #3026 Background : Patients with early stage ER+ve breast cancer have excellent prognosis with ca 90% 5 year disease free survival when treated with endocrine therapy. However for patients who relapse during endocrine therapy additional adjuvant therapy options, such as chemotherapy, are indicated. The challenge is to prospectively identify such patients. The Mammostrat ® test comprises 5 simple immunohistochemical markers (p53, HTF9C, CEACAM5, NDRG1, SLC7A5) which stratify node negative tamoxifen treated patients into low, moderate and high risk groups. We have now tested the efficacy of this panel in a mixed population of node positive/node negative cases treated in a single centre (Edinburgh Breast Unit) with breast conserving surgery.
 Methods: TMAs from a consecutive series (1981-98) of 1,812 women managed by wide local excision and postoperative radiotherapy (45Gy in 20-25 fractions) were collected following appropriate ethical review. Of 1390 cases stained, 197 received no adjuvant hormonal or chemotherapy, 1044 received tamoxifen only as adjuvant therapy and 149 received a combination of hormonal and chemotherapy. Median age at diagnosis was 57, 71% were post-menopausal, 23.9% node positive, median size was 1.5 cm. Samples were stained, using triplicate 0.6mm 2 TMA cores and positivity for p53, HTF9C, CEACAM5, NDRG1, SLC7A5 recorded as previously described. Each case was assigned a Mammostrat score and RFS and OS analysed by marker positivity and Mammostrat score.
 Results: Staining for all 5 antibodies was successful in 1174/1390 (84%) of cases. In the primary analysis of 531 N0/ER+ve Tamoxifen only treated patients Mammostrat was significantly associated with relapse free survival (RFS) in univariate (p=0.025) & multivariate proportional hazards analysis (p=0.01, HR=1.3, 95%C.I. 1.08-1.74). PgR, multifocality and menopausal status were significant co-variates (p Discussion: In the Edinburgh BCS population Mammostrat was predictive of RFS (both local and distant relapses) in N-ve/ER+ve patients treated with tamoxifen alone irrespective of menopausal status. There was a strong correlation between Mammostrat scores and grade, however, in a multivariate analysis Mammostrat contributed significantly to prognostication along with PgR, multifocality and menopausal status. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3026.

Rates of immune cell infiltration in patients with triple-negative breast cancer by molecular subtype

In patients with triple-negative breast cancer (TNBC), tumor-infiltrating lymphocytes (TILs) are associated with improved survival. Lehmann et al. identified 4 molecular subtypes of TNBC [basal-like (BL) 1, BL2, mesenchymal (M), and luminal androgen receptor (LAR)], and an immunomodulatory (IM) gene expression signature indicates the presence of TILs and modifies these subtypes. The association between TNBC subtype and TILs is not known. Also, the association between inflammatory breast cancer (IBC) and the presence of TILs is not known. Therefore, we studied the IM subtype distribution among different TNBC subtypes. We retrospectively analyzed patients with TNBC from the World IBC Consortium dataset. The molecular subtype and the IM signature [positive (IM+) or negative (IM-)] were analyzed. Fisher’s exact test was used to analyze the distribution of positivity for the IM signature according to the TNBC molecular subtype and IBC status. There were 88 patients with TNBC in the dataset, and among them 39 patients (44%) had IBC and 49 (56%) had non-IBC. The frequency of IM+ cases differed by TNBC subtype (p = 0.001). The frequency of IM+ cases by subtype was as follows: BL1, 48% (14/29); BL2, 30% (3/10); LAR, 18% (3/17); and M, 0% (0/21) (in 11 patients, the subtype could not be determined). The frequency of IM+ cases did not differ between patients with IBC and non-IBC (23% and 33%, respectively; p = 0.35). In conclusion, the IM signature representing the underlying molecular correlate of TILs in the tumor may differ by TNBC subtype but not by IBC status.