A newly identified enzyme from Japanese common squid Todarodes pacificus has the ability to biosynthesize d-aspartate.

Amino acids exist in two chiral forms, namely L and D. Although l-amino acids are predominant in vivo, certain limited circumstances have reported the usage of d-amino acids. d-aspartate (Asp), among them, plays crucial physiological roles in living organisms and is biosynthesized from L-Asp by the enzyme named aspartate racemase (AspRase). D-Asp is known to accumulate in large amounts in the nervous system of cephalopods. To understand the function of D-Asp in nervous system in more detail, it is necessary to elucidate its metabolic pathway; however, AspRase gene has not been identified in cephalopods as in the case of mammals. In this study, we successfully identified a novel gene encoding AspRase from the optic ganglion of Japanese common squid Todarodes pacificus. Our discovery of the squid AspRase challenges the prevailing assumption that AspRases across different animals share similar structures. Surprisingly, the squid AspRase is a unique enzyme that differs significantly from known AspRases, being structurally and phylogenetically related to aspartate aminotransferase (AST) and possessing both AspRase and AST activities. The optimum pH and temperature for AspRase activity using L-Asp as a substrate are approximately 7.0 and 20 °C, respectively. Moreover, we have found that AspRase activity is enhanced in the presence of 2-oxoacids. These findings have far-reaching implications for the understanding of enzymology and suggest that yet-to-be-identified mammalian AspRases may also be phylogenetically related to AST, rather than conventional AspRases. Furthermore, our results provide valuable insights into the evolution of the D-Asp biosynthetic pathway.

Hydrogen Peroxide-Triggered Conversion of Boronic Acid-Appended Insulin into Insulin and Its Application as a Glucose-Responsive Insulin Formulation.

p-Boronophenylmethoxycarbonyl (BPmoc) is a protecting group for amines that is removable by treatment with hydrogen peroxide (H2O2). We prepared BPmoc-modified insulin (BPmoc-Ins) and subcutaneously injected the formulation into diabetic rats. The results demonstrated that BPmoc effectively sealed the blood glucose (Glc)-lowering effects of Ins. Conversely, coinjection of BPmoc-Ins and Glc oxidase (GOx) resulted in reduced blood Glc levels, indicating that Ins was generated from BPmoc-Ins through the following reactions: oxidation of endogenous Glc by GOx; production of H2O2 accompanied by Glc oxidation; removal of BPmoc residues by H2O2. These results show the potential of BPmoc-Ins for a Glc-responsive Ins release system.

Cholesterol-binding ability of saponin from Japanese starfish.

Steroidal gylcosides are the predominant metabolites of starfish and are responsible for various biological activities. Some of these activities are recognized as a part of self-defense mechanism of starfish. Cholesterol-binding ability was evaluated with seven starfish crude extracts, where significantly (p < 0.05) highest ability (34%) was observed in Asterias amurensis and the lowest (16%) was attributed in Distolasterias nippon. To characterize the active compound exists in crude saponin from A. amurensis, the extract was subjected to thin layer chromatography following silica gel column chromatography. As the results, seven fractions (fr. A-G) were separated and frs. D and F demonstrated the highest cholesterol-binding ability (32% and 33%, respectively), equivalent to that of the A. amurensis extract. The isolated component (fr. F) was further separated (fr. F1-F3) for structural analysis. Based on cholesterol-binding ability result (29%), fr. F2 was analysed by matrix-assisted laser desorption ionization-time-of-flight mass spectroscopy (MALDI-TOF MS) and then nuclear magnetic resonance spectroscopy (NMR). The compound was identified as thornasteroside A, one of the major bioactive compounds already found in A. amurensis. The discovery of a saponin with cholesterol-binding ability has important implications not only for the utilization of starfish but also for food and pharmaceutical research.

Changes in free amino acid concentrations and associated gene expression profiles in the abdominal muscle of kuruma shrimp (Marsupenaeus japonicus) acclimated at different salinities.

Shrimps inhabiting coastal waters can survive in a wide range of salinity. However, the molecular mechanisms involved in their acclimation to different environmental salinities have remained largely unknown. In the present study, we acclimated kuruma shrimp (Marsupenaeus japonicus) at 1.7%, 3.4% and 4.0% salinities. After acclimating for 6, 12, 24 and 72 h, we determined free amino acid concentrations in their abdominal muscle, and performed RNA sequencing analysis on this muscle. The concentrations of free amino acids were clearly altered depending on salinity after 24 h of acclimation. Glutamine and alanine concentrations were markedly increased following the increase of salinity. In association with such changes, many genes related to amino acid metabolism changed their expression levels. In particular, the increase of the expression level of the gene encoding glutamate-ammonia ligase, which functions in glutamine metabolism, appeared to be associated with the increased glutamine concentration at high salinity. Furthermore, the increased alanine concentration at high salinity was likely associated with the decrease in the expression levels of the the gene encoding alanine-glyoxylate transaminase. Thus, there is a possibility that changes in the concentration of free amino acids for osmoregulation in kuruma shrimp are regulated by changes in the expression levels of genes related to amino acid metabolism.

Molecular characterization of aspartylglucosaminidase, a lysosomal hydrolase upregulated during strobilation in the moon jellyfish, Aurelia aurita.

The life cycle of the moon jellyfish, Aurelia aurita, alternates between a benthic asexual polyp stage and a planktonic sexual medusa (jellyfish) stage. Transition from polyp to medusa is called strobilation. To investigate the molecular mechanisms of strobilation, we screened for genes that are upregulated during strobilation using the differential display method and we identified aspartylglucosaminidase (AGA), which encodes a lysosomal hydrolase. Similar to AGAs from other species, Aurelia AGA possessed an N-terminal signal peptide and potential N-glycosylation sites. The genomic region of Aurelia AGA was approximately 9.8 kb in length and contained 12 exons and 11 introns. Quantitative RT-PCR analysis revealed that AGA expression increased during strobilation, and was then decreased in medusae. To inhibit AGA function, we administered the lysosomal acidification inhibitors, chloroquine or bafilomycin A1, to animals during strobilation. Both inhibitors disturbed medusa morphogenesis at the oral end, suggesting involvement of lysosomal hydrolases in strobilation.

Distant Recurrence Risk after Late Ipsilateral Breast Tumor Recurrence: Results of a Retrospective, Single-Institution Study.

OBJECTIVES: There is limited information regarding risk factors for distant recurrence in patients with late ipsilateral breast tumor recurrence (IBTR). METHODS: Late IBTR was defined as IBTR occurring >5 years after the initial surgery. Seventy-eight patients with late IBTR were reviewed to examine the risk factors of distant recurrence. RESULTS: The negative estrogen receptor and positive HER2 statuses of IBTR were significantly correlated with poorer distant disease-free survival (p=0.03 and 0.02, respectively). Multivariate analyses demonstrated that the HER2 status of IBTR was an independent predictive factor of distant recurrence (p=0.04). CONCLUSIONS: The results of our retrospective, single-institution study revealed that the HER2 status of IBTR was an independent predictive factor of distant recurrence in patients with late IBTR.

Regional lymphatic recurrence after salvage surgery for ipsilateral breast tumor recurrence of breast cancer without local treatment for regional lymphatic basin.

BACKGROUND: There is limited information regarding rates of and risk factors for regional lymphatic recurrence (RLR) after salvage surgery for ipsilateral breast tumor recurrence (IBTR) without local treatment for the regional lymphatic basin. METHODS: One hundred two patients, who underwent salvage breast surgery without local treatment for the regional lymphatic basin (surgery or radiotherapy) for IBTR that relapsed after breast-conserving surgery for primary breast cancer, were reviewed retrospectively to examine the rate of and risk factors for RLR. RESULTS: Of the 102 patients, 9 patients (8.8%) had RLR with a median follow-up period of 3.7 years after salvage breast surgery for IBTR. The estrogen receptor (ER) status and lymphovascular invasion of the recurrent breast tumor were both independent predictive factors of RLR (P = 0.04 and 0.02, respectively). CONCLUSIONS: The rate of RLR was not low in patients with IBTR who received salvage breast surgery only without any treatment for the regional lymphatic basin. The ER status and lymphovascular invasion of the recurrent breast tumor were predictive factors of RLR.

Metastatic gallbladder cancer presenting as numb chin syndrome: A case report and literature review.

Gallbladder cancer (GBC) is an uncommon malignancy that is highly aggressive in the advanced stages. However, it rarely metastasizes to the mandible. Numb chin syndrome (NCS) is a rare neurological manifestation associated with various underlying causes, including occult primary cancers and distant metastases. It is often considered to be a significant indicator of malignancy, and thorough investigation is essential in the presence of unclear etiology. The current study reported on the case of a 69-year-old Japanese woman who presented with numbness and mild pain in the lower lip and chin area for three months. No other systemic symptoms were observed. Immunocytochemical examination revealed the presence of an adenocarcinoma and TNM staging as per the Union for International Cancer Control and the American Joint Committee on Cancer guidelines confirmed stage IVb GBC. Comprehensive full-body positron emission tomography-computed tomography examination using 18F-fluoro-2-deoxy-D-glucose revealed additional bone and soft-tissue metastases. Palliative chemotherapy and radiation treatment were initiated based on the advanced stage of disease at the time of diagnosis. However, the patient succumbed to multiple organ failure six months later. The simultaneous occurrence of GBC, mandibular metastasis and NCS is rare and associated with poor prognosis. Despite the widespread nature of the disease, it can often manifest as non-specific oral symptoms without any systemic indications. The current study emphasizes the critical importance of timely confirmatory testing for accurate diagnosis and initiation of appropriate management for such complex conditions.

Cloning and expression profile of the alanine aminotransferase gene from kuruma shrimp Penaeus japonicus exposed to different salinities.

Several crustaceans including shrimps change the amount of specific free amino acids to regulate the osmotic pressure in their bodies. Kuruma shrimp Penaeus japonicus also increases the concentration of alanine (Ala) in the abdominal muscle following the increase of environmental salinity. In the present study, to elucidate the mechanisms of changes in Ala accumulation of kuruma shrimp depending on salinity, we cloned the gene encoding alanine aminotransferase (ALT), an enzyme involved in Ala biosynthesis, and examined its expression profile. It was found that the full-length kuruma shrimp ALT1 cDNA consisted of 3,301 bp, encoding 514 amino acids, and that all amino acid residues important for ALT activity were conserved. Phylogenetic analysis also indicated that the ALT gene cloned in this study was classified as ALT1. Moreover, we examined the expression levels of the ALT1 gene in the abdominal muscle and the hepatopancreas of kuruma shrimp acclimated at 17‰, 34‰, and 40‰ salinities, resulting that the mRNA levels of the ALT1 genes in both tissues of the shrimp acclimated at 40‰ were significantly higher than those at 17‰ for 12 h (p < 0.05). The mRNA levels of the ALT1 gene in the abdominal muscle of the shrimp acclimated for more than 24 h tended to increase following the increase of environmental salinity. These results indicate that ALT1 is responsible for the increase of free Ala concentration in the abdominal muscle of kuruma shrimp to regulate osmotic pressure at high salinity.

Phenylenediamine derivatives induce GDF-15/MIC-1 and inhibit adipocyte differentiation of mouse 3T3-L1 cells.

Phenylenediamine derivatives can function as a hydrogen donor and reportedly exert various biological actions including cytoprotective effects against oxidative stress, possibly by acting as an antioxidant. Previous studies showed that feeding of such compounds to mice reduced their body weight, but the precise mechanism remains unknown at present. Here, we found that these compounds inhibited the in vitro differentiation of mouse preadipocytes, 3T3-L1 cells, into adipocytes, suggesting that, at least in part, reduced generation of adipocytes might contribute to the observed weight loss in mice. Next, we performed array analysis and found that the expression of GDF-15/MIC-1, which is a TGFß superfamily cytokine, and Trib 3, an intracellular downstream effector of the cytokines, was up-regulated by these derivatives. Thus, we identified the compounds as inducers of GDF-15/MIC-1 and suggest that such induction may have led to inhibition of adipocyte differentiation, which could account for the weight-loss effect of these compounds.

The occurrence of two types of fast skeletal myosin heavy chains from abdominal muscle of kuruma shrimp Marsupenaeus japonicus and their different tissue distribution.

Shrimps belong to the class Crustacea, which forms a large, diverse group in the invertebrates. However, the physiology and biochemistry of their skeletal muscles have been poorly understood compared with those from vertebrates including mammals and fish. The present study focused on myosin, the major protein in skeletal muscle, from adult specimens of kuruma shrimp Marsupenaeus japonicus. Two types of the gene encoding myosin heavy chain (MHC), a large subunit of the myosin molecule, were cloned from abdominal fast skeletal muscle and defined as MHCa and MHCb. Protein analysis revealed that the MHCa isoform was expressed at a higher level than the MHCb isoform. The full-length cDNA clones of MHCa and MHCb consisted of 5929 bp and 5955 bp, respectively, which encoded 1912 and 1910 amino acids, respectively. Both were classified into fast muscle type by comparison with the partially deduced amino acid sequences of fast-type and slow-type (S(1), slow twitch) MHCs reported previously for the American lobster Homarus americanus. The amino acid identities between MHCa and MHCb of kuruma shrimp were 78%, 60% and 72% in the regions of subfragment-1, subfragment-2 and light meromyosin, respectively, and 71% in total. In situ hybridisation using anti-sense RNA-specific probes, along with northern blot analysis using different tissues from abdominal muscle, revealed the different localisation of MHCa and MHCb transcripts in abdominal fast skeletal muscle, suggesting their distinct physiological functions.

SPIO-enhanced magnetic resonance imaging for the detection of metastases in sentinel nodes localized by computed tomography lymphography in patients with breast cancer.

BACKGROUND: Superparamagnetic nanoparticle-enhanced magnetic resonance (MR) imaging has been reported to be a promising improvement for diagnostic imaging of lymph node metastases from various tumors. Moreover, sentinel nodes have been reported to be well identified using computed tomography (CT) lymphography (CT-LG) in patients with breast cancer. The aim of this study was to evaluate MR imaging with superparamagnetic iron oxide (SPIO) enhancement for the detection of metastases in sentinel nodes localized by CT-LG in patients with breast cancer. METHODS: This study included 102 patients with breast cancer and clinically negative nodes. Sentinel nodes were identified by CT-LG, and SPIO-enhanced MR imaging of the axilla was performed to detect metastases in the sentinel nodes. A node was considered nonmetastatic if it showed a homogenous low signal intensity and metastatic if the entire node or a focal area did not show low signal intensity on MR imaging. Sentinel node biopsy was performed, and imaging results were correlated with histopathologic findings. RESULTS: The mean number of sentinel nodes identified by CT-LG was 1.1 (range, 1-3). The sensitivity, specificity, and accuracy of MR imaging for the diagnosis of sentinel node metastases were 84.0%, 90.9%, and 89.2%, respectively. In 4 of 10 patients with micrometastases, metastases were not detected, but all 15 patients with macrometastases were successfully identified. CONCLUSIONS: SPIO-enhanced MR imaging is a useful method of detecting metastases in sentinel nodes localized by CT-LG in patients with breast cancer and may avoid sentinel node biopsy when the sentinel node is diagnosed as disease-free.

Repeat lumpectomy for ipsilateral breast tumor recurrence after breast-conserving treatment.

OBJECTIVES: There are limited data on the outcomes of patients treated with repeat lumpectomy at the time of ipsilateral breast tumor recurrence (IBTR). METHODS: We retrospectively analyzed 78 patients who underwent repeat lumpectomy after IBTR. The risk factors for second IBTR were assessed. RESULTS: The median follow-up period was 40 months. The 5-year second IBTR-free survival rate was 78.8%. Patients with estrogen receptor (ER)-positive or unknown tumors at IBTR had a significantly better second IBTR-free survival rate than those with ER-negative tumors at IBTR (88.3 vs. 55.4%, respectively; p = 0.0022). Multivariate analysis revealed that the ER status of IBTR was a significantly independent predictive factor for second IBTR-free survival (p = 0.0177). The low-risk group for second IBTR was detected using the ER status, disease-free interval, margin status of IBTR, and age at diagnosis (5-year cumulative incidence, 7.0%). CONCLUSION: The ER status of IBTR was a significantly independent predictive factor for second IBTR-free survival. Some patients could safely undergo repeat lumpectomy for IBTR.

Efficacy of oral tegafur-uracil (UFT) as adjuvant therapy as compared with classical cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) in early breast cancer: a pooled analysis of two randomized controlled trials (N.SAS-BC 01 trial and CUBC trial).

Two randomized clinical studies comparing the efficacy of oral UFT (2 years) with that of classical cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) (six courses) have been conducted in patients with resected early breast cancer. We have performed a pooled analysis of these two randomized studies. A pooled analysis was performed using individual patient data from the two trials. Hazard ratios (HRs) were determined with a Cox model stratified by study and adjusted for clinical characteristics. We preplanned to verify the following two hypotheses: UFT is non-inferior to CMF in all patients (hypothesis 1) or in ER-positive patients (hypothesis 2) with respect to relapse-free survival (RFS). Non-inferiority of UFT versus CMF was established if the upper limit of the two-sided confidence interval (CI) of the HR for RFS did not exceed 1.30. Hochberg multiplicity adjustment for the significance level was performed. A total of 1,057 patients were analyzed (CMF, n = 528; UFT, n = 529). Median follow-up time was 5.6 years. The HR for RFS was 1.04 (95% CI, 0.78-1.40) in all patients and 0.79 (97.5% CI, 0.49-1.27) in ER-positive patients. UFT was shown to be non-inferior to CMF in ER-positive patients. An exploratory subgroup analysis showed that RFS was better with UFT than with CMF in ER-positive patients who were 50 years or older (HR, 0.58; 95% CI, 0.34-1.01). UFT is non-inferior to CMF in terms of inhibiting recurrence of ER-positive, early breast cancer.

Prognostic significance of neutropenia on day one of anthracycline-based neoadjuvant chemotherapy in operable breast cancer.

OBJECTIVES: It is currently unknown whether neutropenia during neoadjuvant chemotherapy for early breast cancer is associated with prognosis. METHODS: We retrospectively analyzed 103 breast cancer patients who were treated with neoadjuvant chemotherapy including epirubicin-based chemotherapy followed by docetaxel. The association between neutropenia due to epirubicin-based chemotherapy and distant disease-free survival (DDFS) was assessed. RESULTS: Thirty-one patients (30%) demonstrated neutropenia during the epirubicin-based regimen. Patients without neutropenia showed a significantly (p = 0.004) lower 5-year DDFS rate (64%) than those with neutropenia (97%). In addition, multivariate analysis showed that neutropenia is an independent prognostic factor for DDFS (p = 0.02). CONCLUSION: Neutropenia occurring in early breast cancer patients during the initial neoadjuvant treatment is strongly associated with a better prognosis.

Expression of estrogen receptor beta and phosphorylation of estrogen receptor alpha serine 167 correlate with progression-free survival in patients with metastatic breast cancer treated with aromatase inhibitors.

Aromatase inhibitor (AI) is widely used as an endocrine treatment in postmenopausal patients with hormone receptor-positive breast cancer. To identify useful prognostic factors for patients with metastatic breast cancer treated with AI therapy, we investigated the association between several hormone receptor-related factors and prognosis. The expressions of estrogen receptor-α (ERα), ERß, progesterone receptor, the phosphorylation of ERα serine 118 (Ser118) and ERα Ser167 were examined using immunohistochemical techniques for the primary tumors of 41 patients with metastatic breast cancer who received first-line AI therapy after relapse. To assess the associations of protein expression and phosphorylation levels with progression-free survival (PFS), the levels of each factor were categorized into low and high values at optimal cutoff points. In univariate analysis, high ERα expression and high ERα Ser167 phosphorylation correlated with longer PFS (p = 0.016 and 0.013, respectively). In multivariate analysis, low ERß expression and high ERα Ser167 phosphorylation correlated with longer PFS (p = 0.031 and 0.004, respectively). Patients with both low ERß expression and high ERα Ser167 phosphorylation had longer PFS than the others (p = 0.0107). These data suggest that the expression of ERß and phosphorylation of ERα Ser167 may be useful prognostic factors in patients with metastatic breast cancer who received first-line AI therapy.

Clinical utility of the 70-gene MammaPrint profile in a Japanese population.

OBJECTIVE: van't Veer and colleagues developed a 70-gene prognosis profile known as MammaPrint to identify breast cancer patients who were at low risk of developing metastases. We evaluated the prognostic value of the 70-gene MammaPrint profile in Japanese women with node-negative breast cancer. METHODS: Frozen tumour samples from 102 eligible node-negative breast cancer patients aged 70 or younger were characterized with the MammaPrint array. The patients were treated with breast-conserving therapy or mastectomy with axillary lymph node dissection between December 1998 and August 2001. About 73 percent received adjuvant hormonal therapy and 28 percent received adjuvant chemotherapy. The gene expression profiles obtained by MammaPrint classified the patients as high- or low-genomic risk. The median follow-up was 7.1 years. RESULTS: Among the 102 patients, 20 (20%) were classified as low-genomic risk and 82 (80%) were classified as high-genomic risk. The probability of distant metastasis-free survival at five years was 100% for the low-risk group and 94% for the high-risk group. CONCLUSIONS: The 70-gene MammaPrint prognosis profile accurately identified Japanese breast cancer patients at low risk of developing recurrences. In fact, 100% of the individuals in the low-risk category remained metastasis-free for the duration of the observation period.

Early response to neo-adjuvant chemotherapy in carcinoma of the breast predicts both successful breast-conserving surgery and decreased risk of ipsilateral breast tumor recurrence.

Neo-adjuvant chemotherapy enables us to increase the possibility of breast-conserving surgery for large, bulky tumors. However, several studies have reported that ipsilateral breast tumor recurrences (IBTRs) occur more frequently after neo-adjuvant chemotherapy than originally envisaged. Recently, it was demonstrated that clinical early response after neo-adjuvant chemotherapy predicts pathological complete response. In this study, we assessed the association of clinical early response after neo-adjuvant chemotherapy with successful breast-conserving surgery and IBTR risk. Between 1995 and 2002, 114 patients with T 3.1-6 cm, N 0 or 1, M 0 breast cancer who were candidates for mastectomy but desired breast-conserving surgery were treated with neo-adjuvant chemotherapy. After two cycles of anthracycline-based neo-adjuvant chemotherapy and before surgery, breast tumors were measured by palpation or ultrasound. Clinical response after two cycles of chemotherapy was defined as positive when the largest tumor dimension was reduced by 30% or greater. Median follow-up time was 72 months. After two cycles of neo-adjuvant chemotherapy, 54 (47.4%) of 114 patients achieved an early response. Patients with the early response underwent breast-conserving surgery significantly more frequently than those without the early response (78% versus 58%, p = 0.03). In addition, the early response was significantly correlated with selection of breast-conserving surgery (odds ratio 3.8, p = 0.01) after adjustments for various clinicopathological factors. Patients without the early response showed significantly lower 6-year IBTR-free survival than patients with the early response (75% versus 97%, p = 0.02). In addition, patients with the early response showed significantly higher 6-year disease-free survival rates than those with the early response (p = 0.02). Multivariate analysis showed that the early response was a predictive factor of IBTR-free survival, being independent of other clinicopathological factors. In conclusion, the early response to neo-adjuvant chemotherapy may be a useful predictor of both selection of surgical method and IBTR risk.

Impact of radiation therapy on breast-conserving therapy for breast cancer in Japanese women: a retrospective analyses of multi-institutional experience. Kansai Breast Cancer Radiation Therapy Study Group.

Whole breast radiation therapy (RT) after breast-conserving surgery is sometimes omitted in Japan; however, its impact on the outcome has not been properly evaluated. A multi-institutional retrospective study was conducted to clarify the impact of RT on local control after breast-conserving therapy (BCT). Data were collected from 3576 patients from 37 participating hospitals, of whom 1763 were eligible for analyses. Five hundred and five patients had ipsilateral breast tumor recurrence (IBTR) and 1258 patients did not. Details of IBTR were available for 245 of 505 patients who had IBTR, the location of IBTR was within or adjacent to the original tumor bed in 168 patients (68.6%). IBTR was salvaged with partial mastectomy in 119 patients (48.6%). Second recurrence in the ipsilateral breast was observed in 27 patients (11.0%). Univariate analyses demonstrated that administration of RT, the resection margin status, hormone responsiveness, T stage, N stage and stage were significantly related to IBTR. Multivariate analysis demonstrated that administration of RT, T stage and N stage were significantly correlated to IBTR. Among them, administration of RT had the largest impact on RT and it decreased the risk of IBTR by 77.3%. Omission of RT had the most significant impact on IBTR. RT should be given as a standard component of BCT.

Accuracy of imprint cytology for intraoperative diagnosis of sentinel node metastases in breast cancer.

OBJECTIVE: The aim of this study was to determine the accuracy of imprint cytology for the intraoperative diagnosis of sentinel node metastases in patients with breast cancer. SUMMARY BACKGROUND DATA: Accurate intraoperative diagnosis of sentinel node metastases enables the selection of patients who need axillary lymph node dissection during the same operation. METHODS: This study included 631 patients with clinical T1 breast cancer with clinically negative nodes. Sentinel nodes were serially sectioned at 2-mm intervals. Imprint cytologic samples were made from all cut surfaces and stained with Papanicolaou staining. Patients with positive sentinel nodes underwent immediate axillary lymph node dissection. Those with negative sentinel nodes diagnosed by intraoperative imprint cytology, but positive by final pathologic results, underwent subsequent axillary lymph node dissection. The results of imprint cytology were compared with the final pathologic results using hematoxylin and eosin staining and immunohistochemistry. RESULTS: In 110 of 130 patients with positive sentinel nodes diagnosed by final pathology, imprint cytology of at least one sentinel node was positive. In 17 of 501 patients with tumor-negative sentinel nodes diagnosed by final pathology, imprint cytology of at least one sentinel node was positive. The sensitivity, specificity, and overall accuracy of imprint cytology for the diagnosis of sentinel node metastases were 84.6%, 96.6%, and 94.1%, respectively. Only 20 (3.2%) patients required a second axillary operation in the present study. CONCLUSION: Intraoperative imprint cytology is a useful method for evaluating sentinel node metastasis in patients with breast cancer.