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, RARß2 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, RARß2, 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.

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.

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.

The role of sentinel lymph node biopsy in patients with differentiated thyroid carcinoma.

AIM: To evaluate the "state of art" of clinical role of sentinel lymph node (SLN) biopsy procedure in patients affected by differentiated thyroid carcinoma. METHODS: All papers cited on PubMed/MEDLINE until June 2005, published in English, and referred to the key words "sentinel lymph node biopsy" AND "thyroid carcinoma" OR "thyroid cancer" were reviewed for the purpose of the present study. RESULTS: The first method used for SLN biopsy in thyroid carcinoma patients was the vital blue dye technique. This technique had some disadvantages as: (a) risk of disruption of the lymphatic channels deriving from the thyroid cancer; (b) difficulty in disclosing SLN lying outside the central compartment; (c) parathyroid glands can take up blue dye and, thus, can be misinterpreted as lymph nodes. Some of the above cited disadvantages were overcome by using the lymphoscintigraphy and intraoperative gamma probe technique. A combination of the blue dye and gamma probe technique has also been proposed with synergic results. CONCLUSION: The reported advantages of the SLN biopsy in small differentiated thyroid carcinoma patients can be resumed as follows: (a) better selection of patients who would benefit from compartment oriented nodal dissection; (b) more accurate lymph node staging; (c) better selection of patients who can require (131)I treatment after surgery (SLN positive for metastasis); (d) better identification of SLN located out of the central compartment.

Oncofetal antigen: a tumor-associated fetal antigen immunogenic in man.

Oncofetal antigen (OFA) has been defined with the use of human natural antibodies as a membrane antigen of human cancer cells that cross-reacts with human fetal brain tissues. The immunogen that elicits the antibody is unknown. The present study was undertaken to examine the immunogenicity of the OFA found on tumor cells. Postoperative melanoma patients were immunized with OFA-positive melanoma cells. Anti-OFA reactivities in the immunized sera were titrated by the immune adherence assay with the use of a known OFA-positive cultured melanoma cell line, M14, as target cell. Alloantibodies were excluded by absorption with lymphoblastoid cells autologous to M14. Anti-OFA antibody then was identified by absorption with fetal brain. In 6 months of immunization, 19 of 23 patients produced increased anti-OFA antibodies. The peak titers ranged from 1:16 to 1:2,048. Sera from 18 patients who were not immunized also were tested for 6 months postoperatively, and none had significant increases in antibody titers. The increase of anti-OFA antibody titer in response to the immunization with OFA-positive tumor cells suggests the immunogenic capability of tumor-related OFA in man.

SDZ PSC 833, the cyclosporine A analogue and multidrug resistance modulator, activates ceramide synthesis and increases vinblastine sensitivity in drug-sensitive and drug-resistant cancer cells.

Resistance to chemotherapy is the major cause of cancer treatment failure. Insight into the mechanism of action of agents that modulate multidrug resistance (MDR) is instrumental for the design of more effective treatment modalities. Here we show, using KB-V-1 MDR human epidermoid carcinoma cells and [3H]palmitic acid as metabolic tracer, that the MDR modulator SDZ PSC 833 (PSC 833) activates ceramide synthesis. In a short time course experiment, ceramide was generated as early as 15 min (40% increase) after the addition of PSC 833 (5.0 microM), and by 3 h, [3H]ceramide was >3-fold that of control cells. A 24-h dose-response experiment showed that at 1.0 and 10 microM PSC 833, ceramide levels were 2.5- and 13.6-fold higher, respectively, than in untreated cells. Concomitant with the increase in cellular ceramide was a progressive decrease in cell survival, suggesting that ceramide elicited a cytotoxic response. Analysis of DNA in cells treated with PSC 833 showed oligonucleosomal DNA fragmentation, characteristic of apoptosis. The inclusion of fumonisin B1, a ceramide synthase inhibitor, blocked PSC 833-induced ceramide generation. Assessment of ceramide mass by TLC lipid charring confirmed that PSC 833 markedly enhanced ceramide synthesis, not only in KB-V-1 cells but also in wild-type KB-3-1 cells. The capacity of PSC 833 to reverse drug resistance was demonstrated with vinblastine. Whereas each agent at a concentration of 1.0 microM reduced cell survival by approximately 20%, when PSC 833 and vinblastine were coadministered, cell viability fell to zero. In parallel experiments measuring ceramide metabolism, it was shown that the PSC 833/vinblastine combination synergistically increased cellular ceramide levels. Vinblastine toxicity, also intensified by PSC 833 in wild-type KB-3-1 cells, was as well accompanied by enhanced ceramide formation. These data demonstrate that PSC 833 has mechanisms of action in addition to P-glycoprotein chemotherapy efflux pumping.

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.

FOXC1 is involved in ERα silencing by counteracting GATA3 binding and is implicated in endocrine resistance.

Estrogen receptor-α (ERα) mediates the essential biological function of estrogen in breast development and tumorigenesis. Multiple mechanisms, including pioneer factors, coregulators and epigenetic modifications have been identified as regulators of ERα signaling in breast cancer. However, previous studies of ERα regulation have focused on luminal and HER2-positive subtypes rather than basal-like breast cancer (BLBC), in which ERα is underexpressed. In addition, mechanisms that account for the decrease or loss of ER expression in recurrent tumors after endocrine therapy remain elusive. Here, we demonstrate a novel FOXC1-driven mechanism that suppresses ERα expression in breast cancer. We find that FOXC1 competes with GATA-binding protein 3 (GATA3) for the same binding regions in the cis-regulatory elements upstream of the ERα gene and thereby downregulates ERα expression and consequently its transcriptional activity. The forkhead domain of FOXC1 is essential for the competition with GATA3 for DNA binding. Counteracting the action of GATA3 at the ERα promoter region, overexpression of FOXC1 hinders recruitment of RNA polymerase II and increases histone H3K9 trimethylation at ERα promoters. Importantly, ectopic FOXC1 expression in luminal breast cancer cells reduces sensitivity to estrogen and tamoxifen. Furthermore, in breast cancer patients with ER-positive primary tumors who received adjuvant tamoxifen treatment, FOXC1 expression is associated with decreased or undetectable ER expression in recurrent tumors. Our findings highlight a clinically relevant mechanism that contributes to the low or absent ERα expression in BLBC. This study suggests a new paradigm to study ERα regulation during breast cancer progression and indicates a role of FOXC1 in the modulation of cellular response to endocrine treatment.

The rationale for planned reoperation after unplanned total excision of soft-tissue sarcomas.

Multimodality management of soft-tissue sarcomas of the extremity is often based on the presence or absence of residual primary disease. Reoperation is warranted or radiotherapy doses altered if the physician is aware that the tumor was incompletely excised. Most patients with soft-tissue masses undergo an initial excision before definitive therapy. These initial unplanned total excisions are usually excisional biopsies for presumably benign disease. Ninety patients were reviewed to evaluate the adequacy of unplanned total excision. All patients underwent unplanned supposed total excisions. Most patients were then treated with preoperative intraarterial Adriamycin (Adria Laboratories, Columbus, Ohio) and radiation therapy, followed by wide reexcision of the prior operative field. Forty-six patients (51.1%) had no gross residual tumor in the reoperative specimen. In two patients, there was microscopic but not macroscopic disease. Forty-four patients (48.9%) had identifiable macroscopic residual disease in the reoperative specimen. When comparing these 44 patients with visible (macroscopic) residual tumor to the remaining 46, no differences were seen in age, sex, stage, histologic type, time from excision to reoperation, or size of initial lesion. This previously unrecognized high incidence of gross residual disease must be considered when planning definitive therapy. Unplanned total excisions are inadequate to remove local disease and, despite multimodality therapy, may result in local failure. Reoperation should be a planned part of definitive management for patients with soft-tissue sarcoma of the extremity whenever the initial surgical procedure was done without a histologic diagnosis or was not planned to be a wide excision. If reoperation cannot be performed, radiotherapy doses to treat gross residual disease should be used.

Sentinel lymphadenectomy in breast cancer.

PURPOSE: We previously demonstrated increased detection of axillary metastases using sentinel lymphadenectomy (SLND) and immunohistochemistry. These methods have evolved and we now report our current use of these techniques and our most recent results of axillary staging with SLND. PATIENTS AND METHODS: One hundred seven consecutive women (previously unreported) with breast cancer underwent SLND followed by completion axillary lymphadenectomy (ALND). All sentinel nodes were examined intraoperatively with frozen section and postoperatively with hematoxylin and eosin staining (H&E) plus immunohistochemical staining (IHC) using antibody to cytokeratin. The nonsentinel axillary nodes were examined with H&E, but not IHC. RESULTS: The median age was 56.6 years (range, 28 to 90). Most patients (58.9%) were postmenopausal, most primary tumors (62.6%) were palpable, and most operations (86.9%) were breast-conserving. The mean tumor size was 2.11 +/- 1.38 cm. Sentinel nodes were identified in 100 patients: 42 patients had metastases in sentinel nodes; of these, 28 (66.7%) had no other involved axillary nodes. On average, 1.8 +/- 1.1 sentinel nodes were examined and 20.3 +/- 7.8 nonsentinel nodes were removed. Of seven patients with no identified sentinel nodes, six had a tumor-negative axilla. SLND was 100% predictive of axillary status in these 100 women. CONCLUSION: In this population of breast cancer patients, SLND with frozen section and IHC was a minimally invasive, highly accurate intraoperative method of axillary staging. We are evaluating the elimination of routine ALND for sentinel-node negative women to minimize the morbidity associated with standard dissections. The ability to identify node-negative patients without ALND would be a welcome addition to the management of women with breast cancer.

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

Limitations of specific reverse-transcriptase polymerase chain reaction markers in the detection of metastases in the lymph nodes and blood of breast cancer patients.

PURPOSE: This study was performed to evaluate the potential of specific mRNA markers to detect micrometastases by reverse-transcriptase polymerase chain reaction (RT-PCR) and Southern blot analysis of sentinel lymph nodes (SNs) and blood from patients with breast cancer. PATIENTS AND METHODS: We assessed the specificity of carcinoembryonic antigen (CEA), cytokeratin-19 (CK-19), CK-20, gastrointestinal tumor-associated antigen-733.2 (GA733.2), and mucin-1 (MUC-1) in the blood of healthy donors (n = 13) and lymph nodes from patients without cancer (n = 3) by RT-PCR assay. The sensitivity of the RT-PCR assay for the target mRNA markers was assessed in breast cancer cell lines (n = 4), primary breast tumors (n = 8), and the frozen sections of SNs (n = 22) from 22 patients with American Joint Committee on Cancer (AJCC) stages I to IIIA breast cancer. RESULTS: CK-20 was the only mRNA marker not detected in lymph nodes or blood from patients without cancer. Both the blood and lymph nodes from patients without cancer expressed CEA, CK-19, GA733.2, and MUC-1 mRNA. All four breast cancer cell lines and six of eight primary breast tumors expressed all five mRNA markers. Expression of mRNA by the RT-PCR assay in the frozen-section SNs (n = 12) without metastases by conventional histopathology ranged from 8% (CK-20) to 92% (GA733.2). Detection of RT-PCR cDNA products in frozen-section SNs was increased with Southern blot analysis compared with ethidium bromide gel electrophoresis (EtBr) for all mRNA markers except CK-19. CONCLUSION: CEA, CK-19, GA733.2, and MUC-1 show no diagnostic value as mRNA markers for the detection of micrometastases by the RT-PCR assay because they are expressed in the blood and lymph nodes of patients without cancer. Further studies are needed to assess the sensitivity of CK-20 to detect micrometastases by the RT-PCR assay in the blood and frozen-section SNs of patients with breast cancer.

Presence of a specific antiestrogen binding site on human follicular thyroid carcinoma cell line (UCLA RO 82 W-1): inhibition by an endogenous ligand present in human serum.

A receptor for antiestrogens, distinct from the estrogen receptor, has been identified in several tissues including the MCF-7 breast cancer cell line. Estrogen receptors have also been found in normal and pathological thyroid tissue homogenates. We demonstrate the presence of an antiestrogen binding site (AEBS) on a pure human follicular thyroid carcinoma cell line (UCLA RO 82 W-1) using a 3H-tamoxifen (3H-TAM) binding assay. The binding of 3H-TAM to the AEBS was determined after preincubation (30 min) of the cells with excess 17 beta-estradiol (2 mumol/L). Specific and saturable binding of 3H-TAM to the cells was observed. Displacement of the tracer from its binding site was dose dependent. Scatchard analysis revealed a dissociation constant (Kd) of 73 nmol/L, indicating a binding site with moderate affinity and capacity (72 pmol/10(6) cells). Using this assay we were also able to demonstrate the presence of an endogenous ligand for the AEBS in ethanol extracts of human serum. Cell growth and 3H-thymidine incorporation by the follicular thyroid carcinoma cells were inhibited when the cells were exposed to TAM (1.5 mumol/L). In conclusion, TAM is able to bind to a specific receptor on this follicular thyroid carcinoma cell line, and a natural circulating ligand present in ethanol extracts of human serum interferes with its binding.

Tamoxifen retards glycosphingolipid metabolism in human cancer cells.

In this study we provide evidence that tamoxifen, the widely used breast cancer drug, is a potent antagonist of glycolipid metabolism. When added to the medium of cultured multidrug resistant (MDR) KB-V-1 carcinoma cells, tamoxifen, at 5.0 microM, drastically lowered the levels of glucosylceramide (glc-cer), as evidenced by a reduction in glc-cer mass. In a similar fashion, in cultured human melanoma cells grown with [3H]galactose, tamoxifen inhibited formation of glc-cer by 44%, and retarded lactosylceramide and ganglioside formation by 50 and 35%, respectively. When glc-cer synthase of melanoma was assayed in cell-free incubations, the inclusion of tamoxifen, at a 1:10 molar ratio with ceramide, inhibited glc-cer synthesis by 50%. These results clearly reveal a new action of tamoxifen and thereby pose intriguing questions regarding mechanisms of action in the realm of estrogen receptor-independent modalities, including effects on MDR.

The multidrug resistance modulator SDZ PSC 833 is a potent activator of cellular ceramide formation.

In this study we demonstrate that the multidrug resistance (MDR) modulator PSC 833 is a potent agonist of ceramide metabolism. When added with [3H]serine or [3H]palmitic acid to the culture medium of MCF-7 cells, PSC 833, in a dose-responsive fashion (1-10 microM), increased the levels of [3H]ceramide as much as 16-fold over control. The actual increase in ceramide mass was verified by thin-layer chromatographic chars. Cellular sphingomyelin radioactivity did not decrease during treatment, indicating that PSC 833 does not elicit ceramide formation through a sphingomyelinase pathway. Inclusion of fumonisin B1, an inhibitor of ceramide synthase, blocked formation of ceramide by PSC 833. The results of cell proliferation assays demonstrated a clear correlation between PSC 833 elicitation of ceramide formation and increased cytotoxicity. The MDR modulator and chemical cousin of PSC 833, cyclosporin A, had little impact on cellular ceramide formation. At a concentration of 2.5 microM, cyclosporin A and PSC 833 treatment increased ceramide formation by 20% and 7.5-fold, respectively. These results reveal a new action of PSC 833 which may contribute to its potency as a drug resistance modulator.

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.

Optimal histopathologic examination of the sentinel lymph node for breast carcinoma staging.

Sentinel lymph node dissection is a minimally invasive surgical technique for staging of breast carcinoma. The optimal pathologic examination of the sentinel node (SN) has not yet been determined. Our standard protocol for evaluation of the SN in patients with breast cancer included frozen section at one level, plus paraffin sections at two levels, separated by 40 microm, and stained with hematoxylin and eosin and cytokeratin immunohistochemistry (IHC) at each paraffin section level. In the current study, we evaluated the use of step sections and cytokeratin IHC in 60 SNs (42 consecutive patients) that were tumor-negative on frozen section and hematoxylin and eosin staining at permanent section levels 1 and 2. The SN were reexamined with cytokeratin IHC at eight additional levels (levels 3-10) of the paraffin block, each separated by 40 microm. Previous IHC sections from levels 1 and 2 had shown micrometastases in nine SNs (eight patients) and no tumor cells in the remaining 51 SNs (34 patients). Of the 51 previously negative SNs, only two (4%) SNs from one (3%) patient had metastatic carcinoma cells in levels 3-10. Thus, the additional step sections with cytokeratin IHC did not significantly increase the number of patients with tumor-positive SNs. We currently recommend that the SN be examined with cytokeratin IHC at two levels of the paraffin block. This should optimize sentinel lymph node dissection as a staging technique and minimize the labor and financial burden associated with multiple step sections and IHC stains.

Factors affecting sentinel node localization during preoperative breast lymphoscintigraphy.

UNLABELLED: 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.

Vital dyes in sentinel node localization.

Vital blue dyes were used to show the feasibility and accuracy of intraoperative lymphatic mapping of the sentinel node (SN) in patients with melanoma, breast cancer, and other solid tumors. Surgeons who have successfully completed an adequate number of cases of intraoperative mapping and sentinel lymph node dissection (SLND) can use blue dye alone to localize the SN. However, radiopharmaceutical agents can facilitate intraoperative mapping; preoperative lymphoscintigraphy can identify the location of the SN, and intraoperative mapping with the gamma probe can provide an auditory signal that complements the visual guide provided by the blue dye. Studies are required to establish more clearly the intralymphatic kinetics of the various radiopharmaceutical agents. An ongoing international Phase III trial in melanoma, the 2 upcoming trials in breast cancer, and similar trials for other solid tumors will further clarify the future role of SLND.

Sentinel node localization in breast cancer.

The status of the axillary nodes is the strongest known prognostic variable in patients with early breast cancer, and is routinely used in planning postoperative therapy. Conventional axillary lymph node dissection is limited by sampling error and potential morbidity. Sentinel node techniques have revolutionized the management of axillary nodes. Accurate identification and focused histologic evaluation of the sentinel node allow accurate prediction of the tumor status of other axillary nodes, thereby avoiding the morbidity and expense of a complete axillary dissection in node-negative patients. Radiotracer techniques play an important role in the preoperative and intraoperative localization of the sentinel nodes. Optimal localization of the sentinel node requires the use of both preoperative lymphoscintigraphy and intraoperative radiosensitive probes. Lymphoscintigraphy also identifies patients with lymphatic drainage to sites other than the axilla, thereby allowing more appropriate treatment and follow-up in this subset of patients. Procedures for localizing sentinel nodes require an understanding of the kinetics of the radiopharmaceuticals or other tracers used and the detection devices employed in each institution. Both surgical and nuclear medicine personnel should understand these principles, and close cooperation between surgeons, nuclear medicine physicians, and pathologists is essential for the application of sentinel node techniques.