The Clinicopathologic Characteristics and Clinical Outcomes of Estrogen Receptor-Negative and Progesterone Receptor-Positive Breast Cancer

Backgrounds: Invasive breast cancer patients with estrogen receptor positive (ER+) or progesterone receptor positive (PR+) tumors are treated by similar treatment strategies. Yet the prognosis of ER-PR+ tumor is currently controversial. The aims of this study were to evaluate the clinicopathologic characteristics and the prognosis of patients with ER-PR+ breast cancer.Materials and Methods: 1570 patients who underwent an operation for stage I-III breast cancer from January 1995 to December 2005 were included in this study. The patients were stratified according to the ER/PR phenotype and our study focused on the ER-PR+ phenotype. The clinicopathologic characteristics and the prognosis of patients with the ER-PR+ phenotype were compared with those of the patients with ER+ (ER+PR- or ER+PR+) breast cancer.Results: The mean age at diagnosis was 47.1 years (age range: 20-88) and the mean follow-up was 65.2 months. The hormone receptor phenotype was “ER-PR+” in 75 cases (4.8%) and “ER+ (ER+PR+ or ER+PR-) in 917 cases (58.4%). A patient age < 35 (p=0.002), a high histologic grade (p=0.004) and C-cerbB2 over-expression (p=0.006) were more frequent for the patients with the ER-PR+ tumors. There was a significant difference between the two groups for the mean age (p<0.001), but there was no difference in the nodal status, the tumor size and the presence of vascular invasion. The 5 year and 10 year disease-free survival (DFS) rates of the ER-PR+ group were 67.2% and 55.3%, respectively, and those of the ER+ group were 84.9% and 73.1%, respectively (p <0.001). The 5 year and 10 year overall survival (OS) of the ER-PR+ group were 82.4% and 62.6%, respectively, and those of the ER+ group were 93.4% and 83.3%, respectively. There was significant difference between the two groups for the OS (p =0.001).Conclusion: ER-PR+ tumors have more aggressive clinicopathologic features than ER+ tumors for the patient age, the tumor grade and the presence of C-erbB2 overexpression. Furthermore, ER-PR+ tumors showed a worse prognosis than did the ER+ tumors. Consequently, the treatment modality and the prognosis of the patients with ER-PR+ tumors probably need to be altered from those of the patients with ER+ tumors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4054.

Lapatinib Suppresses RTK-Mediated Signaling through Multiple Signaling Pathways

Background: Activation of tyrosine kinase receptors, including EGFR, HER2, HER3 and HER4, plays a key role in the prognosis of mammary cancer. EGFR and HER2 are validated therapeutic targets; but unfortunately, only a small percentage of patients with EGFR or HER2-overexpressing tumors respond to therapy, and resistance develops even in responsive patients. Lapatinib is a small molecule dual tyrosine kinase inhibitor that suppresses the activation of EGFR and HER2. Completely understanding the molecular mechanisms and protein targets involved in the effects of Lapatinib and other RTK inhibitors can help determine why efficacy varies. This requires the simultaneous identification of specific molecular markers in the complex network of signaling pathways that are modulated by Lapatinib in mammary cancer.Methods and Materials: In this study, female Sprague-Dawley rats (50 days old) were given methylnitrosourea (MNU) by IV injection through the jugular vein (75 mg/kg BW). The rats were palpated for mammary cancers 2 times per week. When a palpable mammary cancer of approximately 200-250 mm2 was present, the rat was administered Lapatinib (150 mg/kg BW/day) by gavage for 7 days. This dose of lapatinib was effective in a prevention study (causing a greater than 80% inhibition of mammary cancers). At sacrifice, the mammary cancer was rapidly removed and fixed for immunohistochemistry or frozen for protein array analysis. Fixed samples were analyzed for phosphorylated EGFR (Tyr1177) and HER2 expression by incubating with specific primary antibodies to detect pEGFR (Tyr1177) or HER2 and secondary antibodies conjugated to a fluorescence dye. Samples were observed by confocal microscopy. Frozen tissues were subjected to Proteome Profiler™ Arrays (R&D, Minneapolis, MN) including phospho-MAP kinase, phospho-kinase, and apoptosis arrays.Results: The results indicated that Lapatinib very effectively suppressed the abundance of both HER2 and phosphorylated EGFR (Tyr1177) compared to tumors from untreated control rats. The array analyses allowed parallel determination of the effect of Lapatinib on the relative levels of protein phosphorylation and apoptosis. Interestingly, unlike Gefitinib (Iressa), which appears to target EGFR and EGFR signaling mediated primarily through ERK MAP kinases, Lapatinib seems to suppress EGFR/HER2 signaling through Src-related proteins, Lyn and Lck, leading to increased cytochrome c release. The complete signaling cascade involves a number of additional signaling molecules, including inhibition of p38δ and γ, JNKs, GSK3α and β, and increased phosphorylation and activation of p27 and p53 potentially leading to apoptosis or cell cycle arrest. A second pathway that might also have a role in the action of Lapatinib involves the suppression of RTK activation of STAT5α and STAT3 potentially leading to decreased cell proliferation.Conclusion: These results suggest that RTK inhibitors have a wide range of potential targets. More work is in progress to continue the dissection of the action of Lapatinib and other RTK inhibitors. Supported by NCI Contract Number HHSN-261200433009C - NO1-CN-55006-72.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1130.

Comparison between Nipple-Areola Saving Subcutaneous Mastectomy and Conventional Subcutaneous Mastectomy in Local Relapse and Prognosis: 5 Year Follow-Up Results

Backgrounds: Skin-sparing mastectomy (SSM) and the even more conservative nipple-areola-skin sparing mastectomy (NASSM) are surgical options for selected patients with indication for mastectomy. But long term result of NASSM is rare and there is no report in Korea. So, we report here 5-year follow-up results of NASSM.Materials and Methods: 202 patients who underwent SSM (N=67) or NASSM (N=135) for breast cancer at our institution between 1996 and 2006 were included in analysis. All patients were followed-up completely. For making a decision of preserving the nipple-areola complex (NAC) during operation, frozen section analysis of the retroareolar glandular tissue with precise localization was done after meticulous dissection of parenchyme under the areola. In the case of positive result in the frozen section or final histology in the NAC, NAC was sacrificed. Intra- or postoperative radiotherapy was not performed. Local relapse (LR) rate and disease free survival (DFS) was analyzed and compared the result between NASSM and SSM.Results: The mean age at diagnosis was 40.2 years old (range 24-65) and mean follow-up months of NASSM was 70.9 months and 60.5 months in SSM. 60 NACs (29.7%) of the all objective NACs were involved by cancer cell at the final histology. The cancer cell involvement to the NAC were more common in invasive carcinoma with extensive intraductal component (p<0.001) or ductal carcinoma in situ component (p=0.048). But tumor size, vascular invasion and nodal status did not affect to involvement of the cancer cell in the NAC. Local recurrences occurred in 8.9% (NASSM) and 6.0% (SSM) of all patients, but there was no significant correlation between the two procedures (p>0.05). Local recurrences occurred at NAC (8 cases), skin flap (3 cases) and chest wall (1 cases) in NASSM procedure group, and 4 skin flaps in SSM group. All NAC recurrences were treated by wide excision of NAC. After treatment of local recurrence, only one case of SSM group preceded to distant metastasis. 5 year Disease-free survival rate was 88.2% in NASSM and 88.4% in SSM group (p>0.05).Conclusion: Our long term follow-up study shows that Nipple-areola-skin sparing mastectomy is oncologically safe procedure for breast cancer in patients who are candidates for mastectomy. Even if relapse is occurred in the NAC, this recurrence cannot affect to the progression of relapse after adequate local treatment. Thus, NASSM is alternative method for SSM with oncological safety and better cosmetic outcome.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3105.

Development of an effective method for dendritic cell immunotherapy of mouse melanoma

Dendritic cell (DC) immunotherapy is a strong candidate for the treatment of incurable cancers especially malignant melanoma. Nevertheless, the proper guideline of DC immunotherapy does not exist. The absence of the guideline is also an obstacle to clinical trials of DC immunotherapy. So we conducted this study in order to develop an effective DC preparation method for immunotherapy in mouse malignant melanoma. Mouse bone marrow-derived DC were stimulated with tumour antigen alone or tumour antigen plus a cocktail (anti-CD40 antibody +TNF-alpha+ IL-1beta) for 8, 24 or 48 h and the characteristics of these DC, such as surface molecules (CD40, CD80, CD86, MHC class II, CCR7), cytokines(IL-12, IFN-gamma, and IL-10), DC-induced T cell proliferation in vitro, and the production of IFN-gamma by those cells, were evaluated. Mice with melanoma were then treated with DC stimulated with tumour antigen alone and tumour antigen plus cocktail for 8 or 48 h. The tumour size and survival rate of these mice were then evaluated. (1) Beneficial clinical effects such as a reduction of tumour size and an increased survival rate were best observed in the group treated with DC stimulated for 8 h with tumour antigen plus cocktail. (2) The single prominent characteristic of DC stimulated for 8 h with tumour antigen plus cocktail was an elevated IL-12 secretion. The cytokine IL-12 was not secreted by other DC. Consequently, proper production of IL-12 was found to be an important requirement for DC used in immunotherapy of mouse melanoma.