FOXC1: an emerging marker and therapeutic target for cancer

The Forkhead box C1 (FOXC1) transcription factor is involved in normal embryonic development and regulates the development and function of many organs. Most recently, a large body of literature has shown that FOXC1 plays a critical role in tumor development and metastasis. Clinical studies have demonstrated that elevated FOXC1 expression is associated with poor prognosis in many cancer subtypes, such as basal-like breast cancer (BLBC). FOXC1 is highly and specifically expressed in BLBC as opposed to other breast cancer subtypes. Its functions in breast cancer have been extensively explored. This review will summarize current knowledge on the function and regulation of FOXC1 in tumor development and progression with a focus on BLBC as well as the implications of these new findings in cancer diagnosis and treatment.

Long-term clinical impact of sentinel lymph node biopsy in breast cancer and cutaneous melanoma

Sentinel lymph node biopsy (SLNB) is based on the hypothesis that the sentinel lymph node (SLN) reflects the lymph-node status and a negative SLN might allow complete axillary lymph node dissection (ALND) to be avoided. Past and current sentinel lymph node clinical trials for breast carcinoma and melanoma address the prognostic and therapeutic utility of SLN dissection (SLND). This technique has already become a standard of care for breast cancer patients and select patients with melanoma. However, it is still important to discuss current techniques and some controversies. This article reviews these issues as well as current guidelines for treatment and management of patients with various findings on SLNB.

Pathologic Examination of Sentinel Lymph Node for Breast Carcinoma

Comprehensive pathologic evaluation of the sentinel lymph node using step sections and cytokeratin immunohistochemistry enhances detection of micrometastases and optimizes the staging of breast carcinoma. This review discusses our current understanding of the pathologic and molecular techniques for sentinel node examination.

Assessment of DNA methylation status in early stages of breast cancer development

Background:

Molecular pathways determining the malignant potential of premalignant breast lesions remain unknown. In this study, alterations in DNA methylation levels were monitored during benign, premalignant and malignant stages of ductal breast cancer development.

Methods:

To study epigenetic events during breast cancer development, four genomic biomarkers (Methylated-IN-Tumour (MINT)17, MINT31, RARβ2 and RASSF1A) shown to represent DNA hypermethylation in tumours were selected. Laser capture microdissection was employed to isolate DNA from breast lesions, including normal breast epithelia (n=52), ductal hyperplasia (n=23), atypical ductal hyperplasia (n=31), ductal carcinoma in situ (DCIS, n=95) and AJCC stage I invasive ductal carcinoma (IDC, n=34). Methylation Index (MI) for each biomarker was calculated based on methylated and unmethylated copy numbers measured by Absolute Quantitative Assessment Of Methylated Alleles (AQAMA). Trends in MI by developmental stage were analysed.

Results:

Methylation levels increased significantly during the progressive stages of breast cancer development; P-values are 0.0012, 0.0003, 0.012, <0.0001 and <0.0001 for MINT17, MINT31, RARβ2, RASSF1A and combined biomarkers, respectively. In both DCIS and IDC, hypermethylation was associated with unfavourable characteristics.

Conclusion:

DNA hypermethylation of selected biomarkers occurs early in breast cancer development, and may present a predictor of malignant potential.

Abstract P1-01-06: Evaluation of the stage IB designation of the 7th edition of the AJCC staging system: Biologic factors are more important

Purpose: The stage IB designation was added to the AJCC 7th edition staging system to denote micrometastasis in patients with T1 tumors. We have previously examined this group and found that receptor status and nuclear grade were better survival discriminates than the presence of micrometastases. The current study was undertaken to validate this finding in a larger cohort from the American College of Surgeons Oncology Group (ACOSOG) Z0010 study.

Methods: Clinicopathologic and outcomes data from patients enrolled on ACOSOG Z0010 were recorded. All patients underwent breast conserving surgery, sentinel lymph node biopsy and whole breast radiation for clinical T1-2, N0 breast cancer. Sentinel lymph nodes were evaluated by H&E locally and if negative, by immunohistochemistry (IHC) at a central laboratory. Patients were staged according to the 7th edition AJCC system and recurrence-free (RFS), disease-specific (DSS) and overall survival (OS) were determined using the Kaplan-Meier method and compared using the log-rank test.

Results: There were 5210 eligible and evaluable patients enrolled on ACOSOG Z0010. AJCC stage distribution was known in 4590 and included: 2849 (62.0%) stage IA, 376 (8.2%) stage IB, 878 (19.1%) stage IIA, 322 (7.0%) stage IIB, and 170 (3.7%) stage III. Median follow-up for the cohort was 9.0 years (range 0–12.6). Five and 10-year RFS, DSS and OS rates for patients with stage IA versus IB disease are shown in table 1.

FOXC1 regulates the functions of human basal-like breast cancer cells by activating NF-κB signaling

Human basal-like breast cancer (BLBC) is an enigmatic and aggressive malignancy with a poor prognosis. There is an urgent need to identify therapeutic targets for BLBC, because current treatment modalities are limited and not effective. The forkhead box transcription factor FOXC1 has recently been identified as a critical functional biomarker for BLBC. However, how it orchestrates BLBC cells was not clear. Here we show that FOXC1 activates the transcription factor nuclear factor-κB (NF-κB) in BLBC cells by increasing p65/RelA protein stability. High NF-κB activity has been associated with estrogen receptor-negative breast cancer, particularly BLBC. The effect of FOXC1 on p65/RelA protein stability is mediated by increased expression of Pin1, a peptidyl-prolyl isomerase. FOXC1 requires NF-κB for its regulation of cell proliferation, migration and invasion. Notably, FOXC1 overexpression renders breast cancer cells more susceptible to pharmacological inhibition of NF-κB. These results suggest that BLBC cells may rely on FOXC1-driven NF-κB signaling. Interventions of this pathway may provide modalities for the treatment of BLBC.

Predicting nipple-areolar involvement using preoperative breast MRI and primary tumor characteristics

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Background: Preoperative assessment of the nipple-areolar complex (NAC) is invaluable when considering nipple-sparing mastectomy (NSM). We hypothesized that breast MRI could predict involvement of the NAC with tumor.

Methods: We compiled clinical, pathologic and imaging data for patients who underwent preoperative breast MRI followed by mastectomy or NSM between 2006 and 2009. Blinded rereview of all MRI studies was performed by a breast MRI imager and compared to initial MRI findings. Multivariate analysis identified variables predicting NAC involvement with tumor.

Results: Of 77 breasts, 18 (23%) had tumor involving or within 1 cm of the NAC. The sensitivity of detecting pathologically confirmed NAC involvement was 61% with history and/or physical exam, and 56% with MRI. Univariate analysis identified the following variables as significant for NAC involvement: large tumors close to the nipple on preoperative MRI, node-positive disease, invasive lobular carcinoma, advanced pathologic T stage, and neoadjuvant chemotherapy. On multivariate analysis, only tumor size > 2 cm and distance to the NAC < 2 cm on MRI maintained significance. Pearson correlation coefficient for MRI size compared to pathologic size was 0.53 (p<0.0001).

Conclusions: MRI is not superior to thorough clinical evaluation for predicting tumor in or near the NAC. However, MRI-measured tumor size and distance from the NAC are correlated with increased risk of NAC involvement. Preoperative history and physical examination, tumor characteristics, plus breast MRI can aid the surgeon in planning for successful NSM.

ACOSOG Z0010: A multicenter prognostic study of sentinel node (SN) and bone marrow (BM) micrometastases in women with clinical T1/T2 N0 M0 breast cancer

CRA504

Background: SN biopsy (SNB) with immunohistochemistry (IHC) of histologically negative SN identifies metastases (mets) not seen by standard histology. The impact of IHC-detected BM mets has been reported in several large single-institution studies. 5,539 patients (pts) were entered into this prospective multicenter observational study to determine the clinical significance of SN and BM mets.

Methods: Patients underwent lumpectomy and SNB with bilateral iliac crest BM aspiration. BM and histologically negative SN were evaluated with IHC in a central laboratory (results not clinically reported). Overall survival (OS), disease-free survival, and locoregional recurrence were determined. Results with OS (the primary endpoint) are reported here.

Results: SN were successfully identified in 5,184 of 5,485 pts (94.5%). Histologic SN mets were found in 1,239 pts (23.9%). IHC detected an additional 350 pts (10.5%) with SN mets. BM mets were identified by IHC in 105 of 3491 examined (3.0%). 5-yr overall survival is shown in the Table . BM IHC positivity significantly predicted decreased OS (p=0.015). A multivariable analysis that included SN and BM status, ER, PR, grade, size, and age showed that neither IHC detected mets in SN (p=0.66) or BM (p=0.08) were independent predictors of OS, although BM status showed a strong trend.

Conclusions: The detection of BM mets by IHC in pts with clinical T1/2 N0M0 breast cancer identifies those pts at significantly increased risk for death; the impact of BM mets on outcome supports and confirms prior studies. In this study, SN IHC-detected mets appear to have no significant impact on OS. The routine examination of SN by IHC is not supported in this patient population by this study.

[Table: see text]

[Table: see text]

ACOSOG Z0011: A randomized trial of axillary node dissection in women with clinical T1-2 N0 M0 breast cancer who have a positive sentinel node

CRA506

Background: Sentinel node biopsy (SNB) eliminates the need for axillary dissection (ALND) in patients whose sentinel node (SN) is tumor-free. However, completion ALND remains the gold standard for patients with a tumor-involved sentinel node. ALND achieves regional control, but its effect on survival remains controversial. The main objective of ACOSOG Z0011 was to compare outcomes of patients with hematoxylin and eosin (H&E) detected metastasis in SN managed with or without ALND and no axillary irradiation.

Methods: Clinically node-negative patients who underwent SN biopsy and had 1 or 2 SN with metastases detected by H&E were randomized to ALND or no further axillary specific treatment. All patients were treated with lumpectomy and opposing tangential field irradiation. Adjuvant systemic therapy was at the discretion of their physicians. Overall survival (OS), disease-free survival (DFS), and locoregional control were evaluated.

Results: 446 patients were randomized to SNB alone and 445 to SNB plus ALND. Patients treated with SNB alone were similar to those treated with SNB + ALND with respect to age, tumor size, Bloom-Richardson score, estrogen receptor status, adjuvant systemic therapy, tumor type, and T stage. Patients randomized to SNB alone had a median of two lymph nodes removed whereas patients randomized to ALND had a median of 17 lymph nodes removed. 17.6% of ALND patients had 3 or more involved nodes compared to 5.0% of SNB patients (p < 0.001). Median follow-up is 6.2 years. 5-year in breast recurrence after ALND was 3.7% compared to 2.1% for SNB (p = 0.16) while 5-year nodal recurrence was 0.6% compared to 1.3% (p = 0.44) respectively. The five-year OS for patients undergoing SNB + ALND is 91.9% compared to 92.5% for SNB alone (p = 0.24), and DFS is 82.2% compared to 83.8% respectively (p = 0.13).

Conclusions: Despite the widely held belief that ALND improves survival, no significant difference was recognized by this study of SN node-positive women. Although the study closed early because of low accrual/event rate, it is the largest phase III study of ALND for node-positive women, and it demonstrates no trend toward clinical benefit of ALND for patients with limited nodal disease.

[Table: see text]

Polypectomy or surgery for malignant colonic polyps: Do we need to change the NCCN guidelines?

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Background: Colonoscopic screening and appreciation of the adenoma-carcinoma sequence have led to increased detection and removal of colonic polyps. The National Comprehensive Cancer Network (NCCN) considers polypectomy alone to be adequate therapy for low-grade invasive T1 polyps that are limited to the head/stalk region and can be excised with negative margins. We examined the implications of this guideline for the general population. Methods: The National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database (1988–2003) was queried to identify patients with invasive T1 colonic polyps. Patients treated with a polypectomy (PP) were compared with those who received a surgical resection (SR). Results: Of 9,162 patients with invasive T1 colonic polyps, 61.6% (11,812) underwent SR and 38.4% (7,350) underwent PP. The percentage of polyps removed increased from 4.2% (812) in 1988 to 9% (1739) in 2003. Patients undergoing SR vs. PP had larger polyps (median size 1.3 vs. 1.0 cm, p <0.001) and higher grade tumors (8.6% vs. 4.7%, p <0.001). The percentage of node positivity was 7% after SR, or 8.9% if at least 12 nodes were resected. The percentage of node positivity reached a surprising 6% in 1,478 patients who underwent SR for low-grade polyps limited to the head/stalk, and nodal status significantly affected the 3-year disease-specific survival of this subgroup: 83% with nodal metastases vs. 96% without nodal metastases (p < 0.003). Conclusions: Malignant colonic polyps with favorable histological features have a 6% risk of lymph node metastases even when removed with negative margins, bringing into question the NCCN recommendation that PP alone is adequate therapy.

No significant financial relationships to disclose.

Role of FOXC1 in regulation of basal-like/triple-negative breast cancer

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Background: Class identification studies have proposed 3 prognostically relevant molecular subtypes of breast cancer: luminal, HER2 and basal-like. The latter is associated with poor prognosis but its molecular basis is not clear. We hypothesized a direct correlation between FOXC1 expression and basal-like breast cancer. Methods: Expression of FOXC1, CK5, CK14, EGFR, c-Kit, αB-crystallin, ITGB4 and FOXC2 in basal-like breast cancer was examined using publicly available microarray datasets. A molecular signature of 40 genes sharing co-ordinate up or down regulation with FOXC1 was identified on one microarray (49 patients) and validated on 5 other microarrays (1,232 patients). The clinical significance of FOXC1 gene expression and the FOXC1 gene signature was evaluated using censored survival data. FOXC1 protein expression was assessed by immunohistochemistry (IHC) of a 96-sample breast cancer tissue microarray. Normal breast epithelial, luminal and basal breast cancer cells transfected with FOXC1 vectors were evaluated for cell proliferation, migration and invasion. Results: FOXC1 was found to be consistently and exclusively upregulated in basal-like triple negative breast cancer and was associated with poor overall survival (p<0.0001). The FOXC1 gene signature accurately predicted the basal-like phenotype. IHC analysis of FOXC1 protein expression in human breast cancers confirmed its potential to be used as a clinical biomarker of basal-like breast cancer. Normal breast epithelial cells and luminal breast cancer cells with low or no FOXC1 expression underwent epithelial-to-mesenchymal transition and displayed increased cellular proliferation, migration, invasion, and expression of basal cell markers when FOXC1 was overexpressed. In contrast, knockdown of FOXC1 by shRNA in basal-like breast cancer cells conferred luminal phenotype. Breast cancer progression-linked signaling pathways like NF-κB and p38MAPK were significantly stimulated in basal-like breast cancer as well as by in vitro FOXC1 overexpression. Conclusions: FOXC1 is a dominant determinant of the basal-like phenotype of breast cancer. We propose FOXC1 to be the single best molecular marker of and a potential therapeutic target for basal-like / triple negative breast cancer.

No significant financial relationships to disclose.

Immunity against breast cancer by TERT DNA vaccine primed with chemokine CCL21

Human telomerase reverse transcriptase (TERT) has been considered a potential tumor-associated antigen for active-specific immunotherapy. However, effective specific tumor antigen-specific immunity has been difficult to induce consistently by various TERT vaccine formulations. New adjuvant strategies have been employed, such as utilizing chemokines to attract T cells and antigen-presenting cells. Chemokine adjuvant strategies may enhance tumor antigen-specific immunity induced by vaccines. Therefore, we utilized chemokine ligand 21 (CCL21) as an adjuvant with a xenogeneic TERT DNA vaccine to induce tumor antigen-specific immunity against TERT-expressing breast cancer. The TERT DNA vaccine consisted of a plasmid containing the COOH terminal end of the TERT (cTERT) gene, encapsulated in multilayered liposomes with hemagglutinating virus of Japan coating. We demonstrated that CCL21 treatment before cTERT DNA vaccine, given intramuscularly, induced significantly higher anti-TERT specific cell-mediated immunity compared to cTERT DNA vaccine alone. Effective tumor antigen-specific immunity was shown both in prophylactic and therapeutic regimens against TS/A murine breast cancer. The study demonstrated that CCL21 administration before cTERT DNA vaccination significantly augmented tumor antigen-specific immunity against breast cancer.

Detection of occult metastatic breast cancer cells in blood by a multimolecular marker assay: correlation with clinical stage of disease

Currently, molecular markers offer the unique opportunity to identify occult metastasis in early stage cancer patients not otherwise detected with conventional staging techniques. To date, well-characterized molecular tumor markers to detect occult breast cancer cells in blood are limited. Because breast tumors are heterogeneous in tumor marker expression, we developed a "multimarker" reverse transcription-PCR assay combined with the highly sensitive electrochemiluminescence automated detection system. Breast cancer cell lines (n = 7), primary breast tumors (n = 25), and blood from normal donors (n = 40) and breast cancer patients [n = 65; American Joint Committee on Cancer (AJCC) stages I-IV] were assessed for four mRNA tumor markers: beta-human chorionic gonadotropin (beta-hCG), oncogene receptor (c-Met), beta 1-->4-N-acetylgalactosaminyl-transferase, and a tumor-associated antigen (MAGE-A3). None of the tumor markers were expressed in any normal donor bloods. Breast cancer cell lines and primary breast tumors expressed beta-hCG, c-Met, beta 1-->4-N-acetylgalactosaminyl-transferase, and MAGE-A3 mRNA. Of the 65 breast cancer patient blood samples assessed, 2, 3, 15, 49, and 31% expressed 4, 3, 2, 1, and 0 of the mRNA tumor markers, respectively. At least two markers were expressed in 20% of the blood specimens. The addition of a combination of markers enhanced detection of systemic metastasis by 32%. In patient blood samples, the MAGE-A3 marker correlated significantly with tumor size (P = 0.0004) and AJCC stage (P = 0.007). The combination of beta-hCG and MAGE-A3 mRNA markers correlated significantly with tumor size (P = 0.04), and the marker combination c-Met and MAGE-A3 showed a significant correlation with tumor size (P = 0.005) as well as AJCC stage (P = 0.018). A multimarker reverse transcription-PCR assay that correlates with known clinicopathological prognostic parameters may have potential clinical utility by monitoring tumor progression with a blood test.

Hepatic cytoreduction followed by a novel long-acting somatostatin analog: a paradigm for intractable neuroendocrine tumors metastatic to the liver

BACKGROUND

Optimal management of symptomatic neuroendocrine tumors that metastasize to the liver is controversial. We investigated aggressive hepatic cytoreduction and postoperative administration of octreotide long-acting release (LAR), a long-acting somatostatin analog.

METHODS

Between December 1992 and August 2000, 31 patients underwent hepatic surgical cytoreduction (20 carcinoid, 10 islet cell, and 1 medullary). All patients had progressive symptoms refractory to conventional therapy.

RESULTS

Hepatic cytoreduction (resection, cryosurgery, and/or radiofrequency ablation) eliminated symptoms in 27 patients (87%) and decreased secretion of hormones by an overall mean of 59%. When minor symptoms returned and/or hormonal levels increased during follow-up, adjuvant therapy was started. Ten patients received adjuvant octreotide LAR once a month, and 21 received other adjuvants. At a median postoperative follow-up of 26 months, 16 patients had progressive/recurrent disease, 13 had died of their disease, and 2 remained free of disease. Median symptom-free interval was 60 months (95% confidence interval, 48-72) with octreotide LAR and 16 months (95% confidence interval, 10-29) with other adjuvants (P = .0007). Two-year symptom-free survival rate was 100% with octreotide LAR and 33% with other adjuvants.

CONCLUSIONS

Hepatic surgical cytoreduction can palliate progressive symptoms associated with liver metastases from intractable neuroendocrine tumors. Postoperative adjuvant therapy with octreotide LAR can prolong symptom-free survival.

Detection of MAGE-A3 in breast cancer patients' sentinel lymph nodes

The detection of occult metastatic breast cancer cells by RT-PCR is limited by the poor specificity of most tumour mRNA markers. MAGE-A3 is a highly specific tumour mRNA marker that is not expressed in non-cancer cells. This study assesses MAGE-A3 mRNA as a molecular marker for the detection of tumour cells in the sentinel lymph nodes (SLN) of breast cancer patients. Serial frozen sections of SLN (n = 121) were obtained from 77 AJCC (American Joint Committee on Cancer) Stage I-IIIA breast cancer patients. MAGE-A3 mRNA analysis of SLN was performed by RT-PCR and Southern blot analysis. Tumour cells were detected in 48 of 121 (40%) SLN from 77 patients by H&E or IHC staining, and 35 of 77 (45%) patients, overall, had histopathologically (H&E and/or IHC) positive SLN. Among histopathologically negative SLN, 28 of 73 (38%) SLN were MAGE-A3 mRNA positive by RT-PCR. Overall, 41 of 77 (53%) patients and 50 of 121 (41%) SLN were positive for MAGE-A3. MAGE-A3 mRNA expression in the SLN occurred more frequently with infiltrating lobular carcinoma (P < 0.001) than with infiltrating ductal carcinoma, adding further evidence of possible phenotypic differences between these 2 subtypes of breast cancer. Due to its high specificity, MAGE-A3 mRNA is a potentially useful marker for detecting breast cancer cells in the SLN. One half of breast tumours expressed MAGE-A3 mRNA, which has important potential implications for antigen-specific targeted immunotherapy.

Current status of sentinel lymphadenectomy in breast cancer

Investigators at many cancer centers have verified that the sentinel node (SN) is the first lymph node to receive lymphatic drainage from a primary breast cancer and therefore the node most likely to contain metastatic tumor cells. When sentinel lymph node dissection (SLND) is undertaken by an experienced multidisciplinary team, the finding of a tumor-free SN almost invariably indicates that the patient has node-negative breast cancer and need not undergo further axillary dissection. At the present time, however, only centers with experience in SLND may abandon completion axillary lymphadenectomy when the SN is free of tumor. In other settings, level I and II axillary dissection is essential until the SLND team has achieved consistently accurate results and the institution has established excellent quality control.

Surgical management of breast cancer in the elderly patient

BACKGROUND

Breast cancer in the older woman is a major health issue and therapeutic challenge. This study asked if presentation, surgical treatment, and outcome of breast cancer are different in elderly women compared with their younger counterparts.

METHODS

There were 816 women < 70 years (younger) and 190 > or = 70 years (older) treated surgically for breast carcinoma between January 1992 and April 2000. Data for younger and older patients was analyzed from our prospective database.

RESULTS

More older women had mammographic lesions (P < 0.006). Breast conservation was the treatment of choice for both groups. Stage, tumor size, histology and disease-specific survival were similar for both. There was no evidence of disease in 93% of cases in the < 70 years group at median follow-up of 38.4 months and 91% for the > or = 70 years group at 44.5 months.

CONCLUSIONS

In our population the presentation, surgical treatment, and survival from breast cancer is similar in older and younger women.

Role for sentinel lymph node dissection in the management of large (> or = 5 cm) invasive breast cancer

BACKGROUND

Sentinel lymph node dissection (SLND) for small, early-stage breast cancer is well accepted. However, the role of SLND for large primary breast cancer is controversial. We investigated the feasibility and clinical applicability of SLND in patients with large (> or = 5 cm) breast cancers and clinically negative axillae.

METHODS

A prospectively entered database was used to identify all patients who underwent surgical management of histopathologically confirmed primary breast carcinomas > or = 5 cm in diameter between September 1991 and August 2000. Patients who had clinically negative axillae and underwent SLND followed by completion axillary lymph node dissection (ALND) were selected for the study. The positivity rate, accuracy rate, and false-negative rate of SLND were determined.

RESULTS

Of the 41 patients selected for the study, 24 had infiltrating ductal carcinoma and 17 had infiltrating lobular carcinoma. Mean tumor size was 7.12 cm (range, 5-23 cm). At least one sentinel lymph node (SLN) was identified in all cases. Thirty patients had tumor-positive SLNs. Axillary metastasis was also identified in one patient who did not have a positive SLN. Thus, SLN status accurately predicted regional nodal status in 98% (40 of 41) of cases. The false-negative rate of SLND was 3% (1 of 31). None of the three patients with SLN micrometastasis, defined as a tumor focus < or = 2 mm, had tumor deposits in nonsentinel axillary lymph nodes. Only SLN macrometastasis (> 2-mm tumor deposit) and primary tumor size > or = 7 cm predicted nonsentinel axillary metastasis with significance on multivariate analysis (P = .008 and P = .046, respectively).

CONCLUSIONS

SLND is feasible and accurate in patients with large breast cancers and clinically negative axillae. Axillary lymph node dissection can be avoided in nearly one third of patients by focused examination of the SLN.

Microsatellite alterations detected in the serum of early stage breast cancer patients

Breast cancer is the most common malignancy affecting women. Advances in screening have resulted in an increasing trend towards detecting earlier stage tumors associated with a longer disease-free survival. Because of this prolonged latency period, it is critical to identify patients early in their disease course who are at increased risk for recurrence, whereby treatment decisions may be altered accordingly based on more precise information. Molecular markers that demonstrate prognostic importance as well as utility for assessing subclinical disease progression offer one such approach. Specifically, circulating microsatellite alterations that reflect those genetic events occurring in tumors and that can be serially assessed through a minimally invasive procedure are a logistically practical method. In this study, serum was collected preoperatively from 56 patients with early stage breast cancer (AJCC stages I/II) and assessed for loss of heterozygosity (LOH) using 8 microsatellite markers. Twelve (21%) of 56 patients demonstrated LOH in their serum for at least one marker. Histopathologic correlation revealed an association between the presence of circulating LOH in serum and those tumors with increased proliferation indices as characterized by an increased diploid index, elevated MIB-1 fraction, and abnormal ploidy. These findings demonstrate the presence of circulating microsatellite alterations in the serum from patients with early stage breast cancer. The association of known poor prognostic features found in tumors with increased nuclear activity not only suggests a possible etiology for their presence, but also offers a potential blood-based surrogate marker for this disease that may demonstrate clinical utility in long-term follow-up studies.

Long-term management and outcome of parathyroidectomy for sporadic primary multiple-gland disease

HYPOTHESIS

For a specific subset of patients with sporadic primary multiple-gland parathyroid disease, subtotal parathyroidectomy results in long-term normocalcemia in the majority of patients, with a minimal complication rate.

DESIGN

Retrospective analysis of outcomes in patients undergoing parathyroidectomy performed by a single surgeon (A.E.G.) between 1984 and 1999.

SETTING

A multidisciplinary endocrine service based at a tertiary referral center.

PATIENTS

Patients undergoing subtotal parathyroidectomy for primary hyperparathyroidism due to sporadic multiple-gland disease identified from a single surgeon's operative records (A.E.G.).

MAIN OUTCOME MEASURES

Data analyzed included demographic factors, operative and pathologic findings, and postoperative and long-term clinical and laboratory results, including calcium and intact parathyroid hormone levels.

RESULTS

Of 379 patients undergoing parathyroidectomy for hyperparathyroidism between 1984 and 1999, 49 (13%) had sporadic multiple-gland disease. Median preoperative calcium and intact parathyroid hormone (iPTH) levels were 2.7 mmol/L (10.8 mg/dL) and 11.79 pmol/L, respectively. Postoperative calcium and iPTH levels were available in 39 patients, and median values were 2.28 mmol/L (9.1 mg/dL) and 2.84 pmol/L, respectively. Long-term follow-up was available for 36 patients (73%), and duration ranged from 6 to 180 months (median, 44 months). Median calcium and iPTH levels at follow-up were 2.3 mmol/L (9.2 mg/dL) and 3.26 pmol/L, respectively, with 3 (8%) of 36 patients having evidence of persistent or recurrent hyperparathyroidism. No patient had biochemical evidence of hypoparathyroidism at long-term follow-up. Five patients (14%) had persistent elevated iPTH levels (range, 8.11-10.95 pmol/L) and normal calcium levels.

CONCLUSIONS

Subtotal parathyroidectomy for sporadic primary multiple-gland disease resulted in a long-term normocalcemia rate of 92%, with minimal complications. Selective subtotal parathyroidectomy can yield excellent long-term results in patients with multiple-gland disease.

Lymphoscintigraphy and lymphatic mapping for identification of sentinel lymph nodes

The recently introduced technique of sentinel lymph node dissection (SLND) may replace complete axillary lymph node dissection for axillary staging of early breast cancer. Successful SLND is predicated on meticulous delineation of the lymphatic pathway and sentinel node(s). Currently employed lymphatic mapping materials include vital blue dyes and radioactive tracers. Techniques of intraoperative lymphatic mapping and SLND using dye, tracer, or both have high success rates in the hands of experienced investigators, but their routine and widespread use awaits resolution of questions about the timing, dose, and type of radioactive tracer; the optimal lymphatic mapping technique; indications and contraindications for SLND; and certification of qualified surgeons, pathologists, and nuclear medicine physicians.

Taxol-induced ceramide generation and apoptosis in human breast cancer cells

PURPOSE

Taxol has emerged as a valuable antimitotic chemotherapeutic agent, particularly in advanced breast and ovarian cancers. Although much is known about cytotoxic mechanisms, the effectiveness of Taxol cannot be solely explained by microtubular interaction. This study was undertaken to determine whether ceramide generation plays a role in Taxol-induced apoptosis.

METHODS

Hormone-independent MDA-MB-468 and hormone-dependent MCF-7 breast cancer cell lines were employed, and ceramide metabolism was characterized using [3H]palmitic acid as lipid precursor.

RESULTS

Exposure of cells to Taxol resulted in enhanced formation of [3H]ceramide. Ceramide increased nearly 2-fold in MDA-MB-468 cells exposed to 50 nM Taxol, and more than 2.5-fold in MCF-7 cells exposed to 1.0 microM Taxol. These concentrations mirrored the EC50 (amount of drug eliciting 50% cell kill) for Taxol in the two cell lines. Use of cell-permeable C6-ceramide as a medium supplement revealed that MDA-MB-468 cells were 20-fold more sensitive to ceramide than MCF-7 cells (P < 0.001). Ceramide was generated as early as 6 h after exposure to Taxol in MDA-MB-468 cells, whereas the earliest signs of apoptosis were detected 12 h after treatment, and by 24 h the apoptotic index was six times that of untreated cells. Both fumonisin B1, a ceramide synthase inhibitor, and L-cycloserine, a serine palmitoyltransferase inhibitor, blocked Taxol-induced ceramide generation, whilst sphingomyelin levels remained unchanged, indicating a de novo pathway of ceramide formation. L-Cycloserine reduced Taxol-induced apoptosis by 30% in MDA-MB-468 cells and totally blocked Taxol-induced apoptosis in MCF-7 cells.

CONCLUSIONS

These results suggest that Taxol-induced apoptosis is, in part, attributable to ceramide and sphingoid bases. This is of relevance to drug mechanism studies, as ceramide is a known messenger of apoptosis. Clinical use of Taxol with ceramide-enhancing agents may maximize cytotoxic potential.

Observation of the breast cancer patient with a tumor-positive sentinel node: implications of the ACOSOG Z0011 trial

Axillary lymph node status has been the most important prognostic factor for breast cancer throughout the past century. During the past decade, intraoperative lymphatic mapping with sentinel lymph node dissection (SLND) has been investigated as an alternative staging modality. This technique may be as accurate as ALND, and certainly is less invasive. Adjuvant treatment recommendations, which historically were made on the basis of lymph node status alone, now take into account primary tumor features, molecular markers, and patient characteristics. This evolution of current treatment patterns is driven in part by the diminishing size of tumors, the simultaneous decrease in the presence of axillary metastases, and a better understanding of tumor-specific risk factors. How do these trends affect the interpretation of a tumor-positive sentinel node (SN)? Can an axilla with a positive SN be observed? Should it be observed? This review examines the implications of a positive SN in the context of smaller tumor size, decreased nodal disease, and increased reliance on alternative prognostic factors for treatment decisions. The historical data comparing ALND to no ALND in clinically node-negative patients is reviewed and discussed in the context of observation for a positive SN. These are the issues underlying the ACOSOG Z0010 and Z0011 trials.

Dermal versus intraparenchymal lymphoscintigraphy of the breast

BACKGROUND AND OBJECTIVE

Dermal and intraparenchymal (IP) injections of radiocolloid have been used for lymphoscintigraphic identification of the sentinel node (SN) in breast cancer. Because of our institute's extensive experience with dermal and IP lymphoscintigraphy for melanoma and breast cancer, we compared patterns of lymphatic migration after both types of injections to identify any differences in drainage patterns or SN identification.

METHODS

Lymphoscintigrams (n = 31) after dermal injections in 30 patients with primary cutaneous melanoma on the breast were compared with lymphoscintigrams after IP injections in 97 consecutive patients with breast cancer. In each case, 400 microCi of filtered 99mTc-sulfur colloid was injected in four quadrants around the tumor or in the biopsy cavity. All lymphoscintigrams were reviewed for patterns of migration and SN location.

RESULTS

Five of 31 (16%) dermal injections demonstrated bilateral axillary migration (n = 3) or a suprasternal SN (n = 2), neither of which was found with IP injections. Conversely, 3 of 97 (3%) IP injections demonstrated direct supraclavicular (n = 2) or costal margin (n = 1) nodes (P = .006), neither of which was found with dermal injections. Low axillary SNs were noted after 26 (84%) dermal and 93 (96%) IP injections (P = .037). The incidence of extra-axillary SNs was 26% (8 of 31) in the dermal group but only 5% (5 of 97) in the IP group (P = .0027).

CONCLUSION

There is a significant difference in lymphatic drainage and SN localization between dermal and IP lymphoscintigraphy. This finding has implications for injection techniques when lymphatic mapping of the SN is undertaken to stage a breast carcinoma.

Ceramide glycosylation potentiates cellular multidrug resistance

Ceramide glycosylation, through glucosylceramide synthase (GCS), allows cellular escape from ceramide-induced programmed cell death. This glycosylation event confers cancer cell resistance to cytotoxic anticancer agents [Liu, Y. Y., Han, T. Y., Giuliano, A. E., and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146]. We previously found that glucosylceramide, the glycosylated form of ceramide, accumulates in adriamycin-resistant breast carcinoma cells, in vinblastine-resistant epithelioid carcinoma cells, and in tumor specimens from patients showing poor response to chemotherapy. Here we show that multidrug resistance can be increased over baseline and then totally reversed in human breast cancer cells by GCS gene targeting. In adriamycin-resistant MCF-7-AdrR cells, transfection of GCS upgraded multidrug resistance, whereas transfection of GCS antisense markedly restored cellular sensitivity to anthracyclines, Vinca alkaloids, taxanes, and other anticancer drugs. Sensitivity to the various drugs by GCS antisense transfection increased 7- to 240-fold and was consistent with the resumption of ceramide-caspase-apoptotic signaling. GCS targeting had little influence on cellular sensitivity to either 5-FU or cisplatin, nor did it modify P-glycoprotein expression or rhodamine-123 efflux. GCS antisense transfection did enhance rhodamine-123 uptake compared with parent MCF-7-AdrR cells. This study reveals that GCS is a novel mechanism of multidrug resistance and positions GCS antisense as an innovative force to overcome multidrug resistance in cancer chemotherapy.

Sentinel lymph node dissection for thyroid malignancy

Sentinel lymph node dissection (SLND) for melanoma and breast cancer has been validated as an accurate technique to assess the status of the lymph nodes in the regional drainage basin. The sentinel node concept has also been investigated in other solid tumors, and more recently, in thyroid carcinoma. SLND using a vital blue dye during thyroidectomy for suspected thyroid malignancy successfully identifies sentinel nodes, with minimal morbidity. Excised sentinel nodes can be examined for micrometastases, and if negative, then the rest of the cervical nodes are likely to be negative. The false negative rate of SLND for thyroid malignancy is unknown, however, because modified neck dissections have not accompanied all cases. The impact that lymph node metastasis in thyroid carcinoma has on prognosis is debatable, unlike breast cancer and melanoma, which therefore makes the utility of thyroid SLND less clear. The technique, results, and morbidity of SLND during thyroidectomy is presented, and its possible utility in well-differentiated and medullary thyroid carcinoma is discussed.

Sentinel lymphadenectomy in node negative breast cancer

SLND, regardless of method, can precisely predict the status of the axillary lymph nodes. Despite differences in technique, the consistent results support the sentinel node hypothesis in breast cancer. The procedure is well tolerated, and staging can be achieved accurately with minimal morbidity. SLND is a minimally-invasive procedure that provides tissue for the pathologist that represents the site most likely to harbor metastases. If a negative sentinel node is removed at SLND, it equates to truly node-negative breast cancer in almost all cases when done by experienced surgeons familiar with the technique. SLND can be mastered by surgeons at several institutions, but requires appropriate training to learn the technique. The team involved in SLND, which consists of the surgeon, pathologist and nuclear medicine physician, must determine its own false negative rate for the procedure, which requires a concomitant ALND so that accuracy is validated. Multicenter randomized clinical trials from the American College of Surgeons and NSABP are in progress, which will evaluate in general, although with different randomization schemes, the outcome of patients who have SLND alone compared to those who have ALND. Before ALND is completely abandoned, these trials must be completed so that the role of SLND in the management of all patients with early breast cancer is fully defined.

Potential and pitfalls of sentinel node detection in breast cancer

The last decade has seen the development of a minimally invasive technique to identify representative nodes--sentinel nodes--that reflect the tumor status of nodes in the axillary lymphatic basin draining a primary breast carcinoma. Sentinel lymph node dissection (SLND), originally developed as an alternative to elective complete lymph node dissection in patients with primary cutaneous melanoma, has been applied successfully to the management of patients with breast cancer. SLND holds promise as a staging technique to replace formal level I and II axillary lymph node dissection in selected patients with breast carcinoma, thus avoiding an unnecessary procedure that has no role in many patients with tumor-free axillae. Under way are two large randomized trials examining the role of SLND for the management of patients with invasive breast carcinoma. Even when tumor is detected in the sentinel node, a focused examination of this node may indicate whether or not completion axillary lymph node dissection is necessary. However, although SLND has great potential, its successful widespread use requires more stringent definition of the sentinel node and standardized guidelines for lymphatic mapping. Each institution must carefully assess the accuracy and consistency of results obtained by its multidisciplinary SLND team.

The use of sentinel lymphadenectomy to identify candidates for postoperative adjuvant therapy of melanoma and breast cancer

Sentinel lymphadenectomy (SLND) is fast becoming the procedure of choice for staging primary breast carcinoma and melanoma. This simpler and less morbid alternative to standard lymph node dissection can increase the rate of detecting nodal disease. Because the tumor status of the regional lymph nodes remains a significant prognostic tool in both diseases, clinicians may use SLND to facilitate selection of patients for adjuvant chemotherapy. Although SLND has been validated by institutions worldwide, it continues to evolve. The following review will examine current data and controversies surrounding this emerging technology.

Apigenin inhibits growth and induces G2/M arrest by modulating cyclin-CDK regulators and ERK MAP kinase activation in breast carcinoma cells

We have previously reported that apigenin inhibits the growth of thyroid cancer cells by attenuating epidermal growth factor receptor (EGF-R) tyrosine phosphorylation and phosphorylation of ERK mitogen-activated protein (MAP) kinase. In this study, we assessed the growth inhibitory effect of apigenin on MCF-7 breast carcinoma cells that express two key cell cycle regulators, wild-type p53 and the retinoblastoma tumor suppressor protein (Rb), and MDA-MB-468 breast carcinoma cells that are mutant for p53 and Rb negative. We found that apigenin potently inhibited growth of both MCF-7 and MDA-MB-468 breast carcinoma cells. The approximate IC50 values determined after 3 days incubation, were 7.8 micrograms/ml for MCF-7 cells, and 8.9 micrograms/ml for MDA-MB-468 cells, respectively. Because the cell cycle studies using FACS showed that both MCF-7 and MDA-MB-468 cells were arrested in G2/M phase after apigenin treatment, we studied the effects of apigenin on cell cycle regulatory molecules. We observed that G2/M arrest by apigenin involved a significant decrease in cyclin B1 and CDK1 protein levels, resulting in a marked inhibition of CDK1 kinase activity. Apigenin reduced the protein levels of CDK4, cyclins D1 and A, but did not affect cyclin E, CDK2 and CDK6 protein expression. In MCF-7 cells, apigenin markedly reduced Rb phosphorylation after 12 h. We also found that apigenin treatment resulted in a dose- and time-dependent inhibition of ERK MAP kinase phosphorylation and activation in MDA-MB-468 cells. These results suggest that apigenin is a promising antibreast cancer agent and its growth inhibitory effects are mediated by targeting different signal transduction pathways in MCF-7 and MDA-MB-468 breast carcinoma cells.

Factors affecting sentinel node localization during preoperative breast lymphoscintigraphy

Variable success rates for identifying axillary (AX) sentinel nodes in breast cancer patients using preoperative lymphoscintigraphy have been reported. We evaluated the effects of age, weight, breast size, method of biopsy, interval after biopsy, and imaging view on the success of sentinel node identification and on the kinetics of radiopharmaceutical migration.

METHODS

Preoperative breast lymphoscintigraphy was performed in consecutive breast cancer patients from February 1998 to December 1998. The ipsilateral shoulder was elevated on a foam wedge and the arm was abducted and elevated overhead. Imaging using this modified oblique view of the axilla (MOVA) started immediately after peritumoral injection of Millipore-filtered 99mTc-sulfur colloid and continued until AX sentinel nodes were identified. Anterior views were obtained after MOVA. AX, internal mammary (IM), and clavicular (CL) basins were monitored in all patients. MOVA was compared with the anterior view for sentinel node identification. Age, weight, breast size, method of biopsy, interval after biopsy, and primary tumor location were evaluated for their effects on sentinel node localization and transit times from injection to arrival at the sentinel nodes.

RESULTS

Seventy-six lymphoscintigrams were obtained for 75 patients. AX sentinel nodes were revealed in 75 (99%) cases. IM or CL sentinel nodes were found in 19 (25%) cases and were not related to tumor location; exclusive IM drainage was present in 1 (1%) case. Identification of AX sentinel nodes was equivalent with MOVA and anterior views in 18 (24%) patients, was better with MOVA in 20 (26%) patients, and was accomplished only with MOVA in 38 (50%) patients. Median transit time was 17.5 min (range, 1 min to 18 h) after injection, and larger breast size was associated with increased transit time. No effect of age, weight, biopsy method, interval from biopsy, or tumor location on transit time was found.

CONCLUSION

Use of MOVA can improve identification of AX sentinel nodes. Although AX drainage is the predominant pattern, a tumor in any portion of the breast can drain to IM sentinel nodes. Transit time was influenced by breast size. Overall short arrival times with this technique allow sentinel lymph node dissection to be performed on the same day as lymphoscintigraphy.

Intraoperative lymphatic mapping and sentinel lymph node dissection in breast cancer

Because the tumor status of the regional lymph nodes is the most important prognostic factor in patients with early-stage breast cancer, accurate histopathologic assessment of these nodes is essential for optimal management, including the selection of candidates for adjuvant systemic therapies. Intraoperative lymphatic mapping using a vital blue dye, with or without a radiocolloid, can identify the first axillary node to receive lymphatic drainage from a primary breast carcinoma. Focused histopathologic assessment of this sentinel node can be used to determine the tumor status of the entire axillary basin. The minimal morbidity and high accuracy of sentinel lymph node dissection (SLND) in breast cancer have been validated by multiple independent investigators, and the data suggest that this surgical technique may eventually replace complete lymph node dissection as the preferred axillary procedure for the management of early-stage disease. In experienced hands, SLND can be successfully performed in more than 90% of eligible breast cancer patients; the tumor status of the sentinel node accurately predicts the status of all axillary nodes in more than 95% of cases. This article reviews the current status, controversies, and future directions of SLND as a staging technique for patients with primary breast carcinoma.

Pathologic features associated with nonsentinel lymph node metastases in patients with metastatic breast carcinoma in a sentinel lymph node

BACKGROUND

To the authors' knowledge it has not yet been determined which patients with primary breast carcinoma and an axillary sentinel lymph node (SN) metastasis have additional metastases in nonsentinel lymph nodes.

METHODS

Pathologic features of the primary breast carcinoma and its SN metastasis were examined in 194 patients and correlated with the tumor status of the non-SNs in the same axillary basin. Two-level cytokeratin immunohistochemistry was applied to the SNs and to non-SNs of cases that were negative by standard hematoxylin and eosin examination.

RESULTS

Lymph node staging based on SN findings, size of the primary tumor, and presence of peritumoral lymphatic vascular invasion (LVI) were associated with non-SN metastasis. The majority (63%) of the 101 patients with SN macrometastases had non-SN metastases. Extranodal hilar tissue invasion in conjunction with SN involvement also was strongly associated with non-SN metastasis (P = 0.0001) but was present in only 65% of patients (35 of 54 patients) with non-SN macrometastases. Approximately 26% of patients (24 of 93 patients) with SN micrometastases (</= 2.0 mm) had non-SN metastases; among these patients only primary tumor size and peritumoral LVI were correlated with non-SN metastasis.

CONCLUSIONS

Detailed pathologic examination of the primary tumor and its SN metastasis may increase precision in the selection of patients for further axillary surgery or radiation therapy.

Origin of metallic particles resembling microcalcifications on mammograms after use of abrasive cautery-tip cleaning pads during breast surgery: experimental demonstration

PURPOSE

To determine if the act of cleaning a cautery tip with an abrasive pad dislodges radiopaque particles that can be transferred to breast tissue during surgery, thereby mimicking microcalcifications at mammography.

MATERIALS AND METHODS

Mock breast surgery was performed by cauterizing bovine liver or fresh, normal, human breast tissue. The cautery tip was rubbed against a cleaning pad five to 20 times in the manner used intraoperatively and was touched on separate breast tissue specimens two to six times. Specimen radiography was then performed. Thirty-six breast specimens were used in three experiments, including 28 used for the experimental conditions and eight control specimens.

RESULTS

Particles collected from the cleaning pads resembled microcalcifications. After cauterization of liver, breast tissue, or both, in series, particles transferred from the cautery tip to breast tissue specimens could be identified on specimen radiographs. Transfer of particles after cautery of breast tissue occurred with increased numbers of rubs and specimen contacts.

CONCLUSION

Radiopaque aluminum oxide particles from abrasive cautery-tip cleaning pads can be dislodged and transferred to breast tissue during surgery. Scrutiny of high-detail, spot-compression, magnification mammograms will help identify these particles. Simple measures to mitigate particle transfer during breast surgery can prevent this problem and obviate a potential second procedure to remove particles mistaken for microcalcifications.

Does sentinel lymphadenectomy improve staging and alter therapy in elderly women with breast cancer?

BACKGROUND

Routine axillary lymph node dissection (ALND) for elderly women with invasive breast cancer has been questioned because it rarely alters therapy yet carries a significant morbidity rate. Sentinel lymphadenectomy (SLND) improves axillary staging and alters therapy in women with T1 breast cancer, but it is not clear whether SLND alters therapy in elderly women with breast cancer.

METHODS

A prospective breast cancer data base was used to identify women 70 years old and older who underwent SLND for axillary staging of invasive breast cancer between 1991 and 1998.

RESULTS

There were 75 invasive breast cancers in 73 women. The mean patient age was 74.5 years (range, 70-90 years). Median tumor size was 1.4 cm (range, 0.1-6.2 cm). Of the 75 tumors, 42 (56%) had favorable primary characteristics; the remaining tumors had unfavorable characteristics. SLND was performed alone in 17 cases (23%) and was followed by completion ALND in 58 cases (77%). Positive lymph nodes were identified in 32 cases (43%); 26 (81.3%) were detected by hematoxylin and eosin stains, and 6 (18.7%) were detected by immunohistochemistry alone. Five patients (6.9%) received adjuvant chemotherapy. Seven patients (9.6%) received axillary/supraclavicular radiation for positive nodes. Ten (13.7%) of 73 patients had obvious alterations in therapy because of axillary nodal status. As a result of SLND, 3 (13.6%) of 22 patients with tumors 1.0 cm or smaller received tamoxifen, and 7 (15%) of 46 patients with tumors between 1.0 and 3.0 cm in size had changes in therapy. When patient and tumor characteristics were analyzed to determine relationships to therapeutic decision-making, nodal status was the variable most significantly associated with changes in therapy (P = .0001).

CONCLUSIONS

SLND improves axillary staging in elderly women with invasive breast cancer. Results of immunohistochemistry do not alter therapy in this group of individuals (P = .6367). In patients with small primary tumors, SLND alters therapy by increasing the number of patients receiving tamoxifen. In addition, SLND affects adjuvant systemic chemotherapy and regional radiotherapy in a significant number of patients with larger tumors, particularly tumors between 1.0 and 3.0 cm.

Prospective observational study of sentinel lymphadenectomy without further axillary dissection in patients with sentinel node-negative breast cancer

PURPOSE

Immediate complete axillary lymphadenectomy (ALND) after sentinel lymphadenectomy (SLND) has confirmed that tumor-negative sentinel nodes accurately predict tumor-free axillary nodes in breast cancer. Therefore, we hypothesized that SLND alone in patients with tumor-negative sentinel nodes would achieve axillary control, with minimal complications.

PATIENTS AND METHODS

Between October 1995 and July 1997, 133 consecutive women who had primary invasive breast tumors clinically </= 4 cm in diameter and no axillary lymphadenopathy were prospectively entered onto a trial of SLND using vital blue dye. Sentinel nodes were examined by standard microscopy or immunohistochemistry. SLND was the only axillary surgery if sentinel nodes were tumor-free. Completion ALND was performed only if sentinel nodes contained metastases or if they were not identified. Excluded from subsequent analysis were patients with unsuspected multifocal carcinoma and those who refused completion ALND. The complication and axillary recurrence rates after SLND without ALND were determined.

RESULTS

Sentinel nodes were identified in 132 (99%) of 133 patients. Eight patients were excluded from further analysis. Of the 125 assessable patients, 57 had tumor-positive sentinel nodes and one had an unsuccessful mapping procedure; these patients underwent completion ALND. In the remaining 67 patients (54%), SLND was the only axillary procedure. Complications occurred in 20 patients (35%) undergoing ALND after SLND but in only two patients (3%) undergoing SLND alone (P =.001). There were no local or axillary recurrences at a median follow-up of 39 months.

CONCLUSION

Complication rates are negligible after SLND alone. An absence of axillary recurrences supports SLND as an accurate staging alternative for breast cancer and suggests that routine ALND can be eliminated for patients with histopathologically negative sentinel nodes.

Uncoupling ceramide glycosylation by transfection of glucosylceramide synthase antisense reverses adriamycin resistance

Previous work from our laboratory demonstrated that increased competence to glycosylate ceramide conferred adriamycin resistance in MCF-7 breast cancer cells (Liu, Y. Y., Han, T. Y., Giuliano, A. E. , and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146). This was achieved by cellular transfection with glucosylceramide synthase (GCS), the enzyme that converts ceramide to glucosylceramide. With this, we hypothesized that a decrease in cellular ceramide glycosylation would result in heightened drug sensitivity and reverse adriamycin resistance. To down-regulate ceramide glycosylation potential, we transfected adriamycin-resistant breast cancer cells (MCF-7-AdrR) with GCS antisense (asGCS), using a pcDNA 3.1/his A vector and developed a new cell line, MCF-7-AdrR/asGCS. Reverse transcription-polymerase chain reaction assay and Western blot analysis revealed marked decreases in both GCS mRNA and protein in MCF-7-AdrR/asGCS cells compared with the MCF-7-AdrR parental cells. MCF-7-AdrR/asGCS cells exhibited 30% less GCS activity by in vitro enzyme assay (19.7 +/- 1.1 versus 27.4 +/- 2.3 pmol GC/h/microg protein, p < 0.001) and were 28-fold more sensitive to adriamycin (EC(50), 0.44 +/- 0.01 versus 12.4 +/- 0.7 microM, p < 0. 0001). GCS antisense transfected cells were also 2.4-fold more sensitive to C(6)-ceramide compared with parental cells (EC(50) = 4. 0 +/- 0.03 versus 9.6 +/- 0.5 microM, p < 0.0005). Under adriamycin stress, GCS antisense transfected cells compared with parental cells displayed time- and dose-dependent increases in endogenous ceramide and dramatically higher levels of apoptotic effector, caspase-3. Western blotting showed that adriamycin sensitivity, introduced by asGCS gene transfection, was independent of P-glycoprotein and Bcl-2 expression. In summary, this work shows that transfection of GCS antisense tempers the expression of native GCS and restores cell sensitivity to adriamycin. Therefore, limiting the potential to glycosylate ceramide, which is an apoptotic signal in chemotherapy and radiotherapy, provides a promising approach to combat drug resistance.

SDZ PSC 833 the drug resistance modulator activates cellular ceramide formation by a pathway independent of P-glycoprotein

SDZ PSC 833 (PSC 833) is a new multidrug resistance modulator. Recent studies have shown that the principal mechanism of action of PSC 833 is to bind P-glycoprotein (P-gp) and prevent cellular efflux of chemotherapeutic drugs. We previously reported that PSC 833 increases cellular ceramide levels. The present study was conducted to determine whether the impact of PSC 833 on ceramide generation is dependent on P-gp. Work was carried out using the drug-sensitive P-gp-deficient human breast adenocarcinoma cell line, MCF-7, and drug resistant MCF-7/MDR1 clone 10.3 cells (MCF-7/MDR1), which show a stable MDR1 P-gp phenotype. Overexpression of P-gp in MCF-7/MDR1 cells did not increase the levels of glucosylceramide, a characteristic which has been associated with multidrug resistant cells. Treatment of MCF-7 and MCF-7/MDR1 cells with PSC 833 caused similar ceramide elevation, in a dose-responsive manner. At 5.0 microM, PSC 833 increased ceramide levels 4- to 5-fold. The increase in ceramide levels correlated with a decrease in survival in both cell lines. The EC50 (concentration of drug that kills 50% of cells) for PSC 833 in MCF-7 and MCF-7/MDR1 cells was 7.2 +/- 0.6 and 11.0 +/- 1.0 microM, respectively. C6-Ceramide exposure diminished survival of MCF-7 cells; whereas, MCF-7/MDR1 cells were resistant to this short chain ceramide analog. Preincubation of cells with cyclosporine A, which has high affinity for P-gp, did not diminish the levels of ceramide generated upon exposure to PSC 833. These results demonstrate that PSC 833-induced cellular ceramide formation occurs independently of P-gp. As such, these data indicate that reversal of drug resistance by classical P-gp blockers may be modulated by factors unrelated to drug efflux parameters.

Role of sentinel lymph node dissection in breast cancer

The sentinel node concept is valid for penile cancer, melanoma, breast cancer and is probably also applicable to other solid malignancies. Sentinel nodes are the one or two initial nodes in the regional nodal drainage basin encountered by the lymphatic effluent from a tumour, which can be identified with an injection of vital dye or other lymphogogue. Sentinel lymph node dissection (SLND), a minimally invasive procedure with negligible morbidity, has therefore been utilized as an alternative to complete axillary lymph node dissection (ALND) for staging breast cancer. Examination of sentinel nodes provides a focused histopathological assessment of tissue most likely to harbour metastases, providing enhanced staging accuracy with a low false-negative rate. Tumour-free sentinel nodes are predictive of a tumour-free axilla, thereby allowing for the possibility of SLND without ALND and sparing patients the morbidity of ALND. Most of the experience from SLND has been obtained for axillary sentinel nodes. However, sentinel nodes have been identified in nonaxillary sites, such as the internal mammary nodes, but data on SLND for these regions is scarce. The ultimate role of SLND in breast cancer, which may be to identify sentinel-node-negative patients or even those with sentinel node metastases who can safely avoid ALND without sacrificing regional control and possibly gain a therapeutic benefit, cannot be defined before we have the results of large trials that are currently in progress.

Biopsy method and excision volume do not affect success rate of subsequent sentinel lymph node dissection in breast cancer

INTRODUCTION

Sentinel lymph node dissection (SLND) is becoming a recognized technique for accurately staging patients with breast cancer. Its success in patients with large tumors or prior excisions has been questioned. The purpose of this study was to evaluate the effect of biopsy method, excision volume, interval from biopsy to SLND, tumor size, and tumor location on SLND success rate.

METHODS

Consecutive patients who underwent SLND followed by completion axillary lymph node dissection from October 1991 to December 1995 were analyzed. Included were cases performed early in the series before the technique was adequately developed. Excision volume was derived from the product of three dimensions as measured by the pathologist. Two end points were analyzed: sentinel node identification rate and accuracy of SLND in predicting axillary status. Univariate analyses using chi2 or Fisher's exact test for categorical variables and Wilcoxon rank sums for continuous variables were performed. Multivariate analysis was performed using logistic regression.

RESULTS

There were 284 SLND procedures performed on 283 patients. Median age was 55 years. The most recent biopsy method used before SLND was stereotactic core biopsy in 41 (14%), fine-needle aspiration in 62 (22%), and excision in 181 (64%) procedures. The mean excision volume was 32 ml with a range of 0.3-169 ml. The mean time from biopsy to SLND was 17 days with a range of 0-140 days. The mean tumor size was 2.0 cm (15 Tis [5%], 184 T1 [65%], 72 T2 [25%], and 13 T3 [5%]). Tumors were located in the outer quadrants in 74%, the inner quadrants in 18%, and subareolar region in 8%. The sentinel node was identified in 81%, and 39% had metastases. There were three false-negative cases early in the series. Sensitivity was 97%, and accuracy was 99%. Negative predictive value was 98% in cases in which the sentinel node was identified. On the basis of biopsy method, excisional volume, time from biopsy to SLND, tumor size, and tumor location, there was no statistically significant difference (P>.05) in sentinel node identification rate or accuracy of SLND.

CONCLUSIONS

SLND has a high success rate in breast cancer patients regardless of the biopsy method or the excision volume removed before SLND. In addition, the interval from biopsy to SLND, tumor size, and tumor location have no effect on the success rate of SLND, even in this series which included patients operated on before the technique was adequately defined. Patients with breast cancers located in any quadrant and diagnosed either with a needle or excisional biopsy could be evaluated for trials of SLND.