A case of undifferentiated carcinoma with osteoclast-like giant cells of the pancreas derived from an intraductal papillary mucinous neoplasm.

Pancreatic undifferentiated carcinoma with osteoclast-like giant cells (UC-OGC) is an extremely rare and aggressive malignancy. We report the case of a 71-year-old male who presented with a solid-and-cystic mass in the pancreatic head. The cut section of the pancreaticoduodenectomy specimen showed hemorrhagic polypoid lesions localized to the cyst spaces. Histological examination revealed a cystic background as an intraductal papillary mucinous neoplasm (IPMN) with low-grade dysplasia, while the intra-cystic polypoid mass was morphologically identical to giant cell tumors (GCT) of bone and soft tissue, consisting of a mixture of mononuclear histiocyte-like cells and multinucleated osteoclast-like giant cells. Nuclei of the mononuclear cells were similar to those of the multinucleated giant cells, showing no obvious atypia. The mononuclear cells were diffusely immunoreactive for CD163 and completely negative for all examined epithelial markers. Genetic analysis showed both the IPMN and the GCT-like components harbored identical double mutations of KRAS (G12V) and GNAS (R201C), and confirmed a diagnosis of UC-OGC originating from IPMN. This case emphasized that pancreatic UC-OGC can provide bland morphology, which is morphologically and immunohistochemically undistinguishable from GCT of the bone and soft tissue. Our study also highlights the importance of genetic analyses in properly diagnosing and managing such patients.

On-tissue polysulfide visualization by surface-enhanced Raman spectroscopy benefits patients with ovarian cancer to predict post-operative chemosensitivity.

Chemosensitivity to cisplatin derivatives varies among individual patients with intractable malignancies including ovarian cancer, while how to unlock the resistance remain unknown. Ovarian cancer tissues were collected the debulking surgery in discovery- (n = 135) and validation- (n = 47) cohorts, to be analyzed with high-throughput automated immunohistochemistry which identified cystathionine γ-lyase (CSE) as an independent marker distinguishing non-responders from responders to post-operative platinum-based chemotherapy. We aimed to identify CSE-derived metabolites responsible for chemoresistant mechanisms: gold-nanoparticle (AuN)-based surface-enhanced Raman spectroscopy (SERS) was used to enhance electromagnetic fields which enabled to visualize multiple sulfur-containing metabolites through detecting scattering light from Au-S vibration two-dimensionally. Clear cell carcinoma (CCC) who turned out less sensitive to cisplatin than serous adenocarcinoma was classified into two groups by the intensities of SERS intensities at 480 cm-1; patients with greater intensities displayed the shorter overall survival after the debulking surgery. The SERS signals were eliminated by topically applied monobromobimane that breaks sulfane-sulfur bonds of polysulfides to result in formation of sulfodibimane which was detected at 580 cm-1, manifesting the presence of polysulfides in cancer tissues. CCC-derived cancer cell lines in culture were resistant against cisplatin, but treatment with ambroxol, an expectorant degrading polysulfides, renders the cells CDDP-susceptible. Co-administration of ambroxol with cisplatin significantly suppressed growth of cancer xenografts in nude mice. Furthermore, polysulfides, but neither glutathione nor hypotaurine, attenuated cisplatin-induced disturbance of DNA supercoiling. Polysulfide detection by on-tissue SERS thus enables to predict prognosis of cisplatin-based chemotherapy. The current findings suggest polysulfide degradation as a stratagem unlocking cisplatin chemoresistance.

Ovarian Sertoli-Leydig Cell Tumor With Heterologous Hepatocytes and a Hepatocellular Carcinomatous Element.

Sertoli-Leydig cell tumors are a group of tumors composed of variable proportions of Sertoli cells, Leydig cells, and sometimes heterologous elements. We describe the case of a 68-yr-old woman who presented with abdominal distention. A computed tomographic scan revealed a large right adnexal mass without evidence of intrahepatic tumors, and a complete cytoreductive surgery was performed. Pathologic examination revealed a moderately differentiated Sertoli-Leydig cell tumor with various heterologous elements, including gastrointestinal-type glands, insular carcinoid, and aggregations of hepatocytes without significant cytologic atypia. Moreover, adjacent to these hepatocytes, extensive overgrowth of highly atypical hepatocyte-like cells, providing a striking morphologic similarity to hepatocellular carcinoma of the liver, was identified. Both the heterologous hepatocytes and hepatocellular carcinomatous tumor cells were immunohistochemically positive for alpha-fetoprotein, hepatocyte paraffin 1, and arginase-1. Some Sertoli cells adjacent to the heterologous hepatocytes were also positive for alpha-fetoprotein and hepatocyte paraffin 1. The present case showed that a tumor morphologically and immunohistochemically analogous to hepatocellular carcinoma of the liver can arise in the ovary, in association with Sertoli-Leydig cell tumors.

Acute gastritis caused by concurrent infection with Epstein-Barr virus and cytomegalovirus in an immunocompetent adult.

Herein, we describe an extremely rare case of gastritis due to concurrent infection with Epstein-Barr virus (EBV) and cytomegalovirus (CMV) occurring in an immunocompetent adult. The patient was a 35-year-old man who presented with slight fever, nausea, anorexia, weight loss for 3 weeks, mild transaminitis, and leukocytosis with atypical lymphocytes in peripheral blood. The clinical presentation and elevated IgM titers to both EBV-VCA and CMV strongly suggested infectious mononucleosis syndrome caused by co-infection with EBV and CMV. A computed tomographic scan of the abdomen showed diffuse thickening of the gastric wall mimicking linitis plastica, and upper endoscopy revealed thickened and eroded mucosa throughout the stomach. Histologic examination of gastric biopsies showed a dense lymphoid and neutrophilic infiltrate in the lamina propria with erosion. In situ hybridization assay revealed many lymphocytes positive for EBV-encoded RNA. Moreover, immunohistochemistry using an anti-CMV monoclonal antibody identified some CMV-positive cells (i.e. foveolar epithelium and endothelium). We finally diagnosed this case as gastric involvement in infectious mononucleosis, and the patient recovered without the administration of antiviral drugs. To our knowledge, this is the first reported case of gastritis co-infected with EBV and CMV, as a manifestation of infectious mononucleosis in an immunocompetent adult.

Plasmablastic lymphoma presenting as a ureteral polypoid mass.

Plasmablastic lymphoma (PBL) is a rare and aggressive subtype of B-cell lymphoma, which occurs typically in the oral cavity of human immunodeficiency virus (HIV)-positive patients. We report a case of a 44-year-old HIV-positive patient with a solitary polypoid mass of the left ureteropelvic junction, causing unilateral hydronephrosis and clinically mimicking urothelial carcinoma. A laparoscopic nephroureterectomy was performed, and pathological examinations revealed the mass as PBL. PBL can present in various forms, even as a polypoid mass of the upper urinary tract, and it should be considered in the differential diagnosis of any mass detected in the HIV-positive patients.

Expression of doublecortin and CaM kinase-like-1 protein in serrated neoplasia of the colorectum.

The adenoma-carcinoma sequence (ACS) and the serrated pathway are two distinct developmental routes leading to the formation of colorectal carcinoma. Recently, the doublecortin and CaM kinase-like-1 protein (DCLK1) has been reported to serve as an intestinal cancer stem cell marker and has been demonstrated to be overexpressed through the ACS; however, there is a lack of reports on the role of DCLK1 in the serrated pathway. To clarify the correlation between DCLK1 protein expression and clinicopathological characteristics of the serrated tumorigenic pathway, the present study used immunohistochemistry to examine the expression of DCLK1 in endoscopically resected samples of 62 serrated polyps [20 hyperplastic polyps (HPs), 16 traditional serrated adenomas (TSAs) and 26 sessile serrated adenoma-polyps (SSA/Ps)], as well as 20 non-serrated adenomas, 20 carcinoma in adenomas (CIAs) and 18 early pure colorectal carcinomas without any adenoma component (EPCs). Based on immunostaining score, high DCLK1 expression was detected in 20.0% of HPs (23.1% of microvesicular HPs and 14.3% of goblet cell HPs), 37.5% of TSAs, 7.7% of SSA/Ps, 80.0% of non-serrated adenomas, 75.0% of CIAs and 50.0% of EPCs. Negative or low DCLK1 expression was frequently observed in TSAs (P<0.005), SSA/Ps (P<0.00001) and EPCs (P<0.04) compared with non-serrated adenomas and CIAs. In addition, negative or low DCLK1 expression was significantly more frequent in SSA/Ps (92.3%) compared with TSAs (62.5%; P<0.05). Thus, the expression pattern of DCLK1 between the serrated pathway and ACS differed, indicating that DCLK1 expression may perform a secondary role in serrated tumorigenesis. In addition, the data indicates that EPCs may contain tumors derived from the serrated pathway as well as the ACS.

Protein expression of Fragile Histidine Triad and cyclooxgenase-2 in serrated neoplasia of the colorectum.

The adenoma-carcinoma sequence (ACS) and the serrated pathway are two distinct developmental routes leading to the formation of colorectal carcinoma (CRC). However, the mechanism triggered by the serrated pathway remains unclear. Therefore, to clarify the molecular and clinicopathological characteristics of the serrated tumorigenic pathway, immunohistochemistry was used to examine the expression of Fragile Histidine Triad (FHIT), cyclooxygenase-2 (COX-2), MutL homolog 1 (MLH1), MutS protein homolog 2 (MSH2) and P53 in endoscopically resected samples of 62 serrated polyps. These samples included 20 hyperplastic polyps (HPs), 16 traditional serrated adenomas (TSAs), 26 sessile serrated adenoma/polyps (SSA/Ps), 20 non-serrated adenomas, 20 carcinoma in adenomas (CIAs) and 18 early pure CRCs without any adenoma component (EPCs). FHIT expression was markedly reduced or absent in 50% of TSA samples, 92.3% of SSA/Ps and 44% of EPCs, but only rarely in HPs, non-serrated adenomas and CIAs. COX-2 expression was more common in non-serrated adenomas compared with in serrated polyps, and was present in 25 and 3.2% of the cases respectively (P<0.01). Furthermore, COX-2 expression was more frequent in CIAs (60%) compared with in EPCs (22.2%; P<0.05). The incidence of negative COX-2 expression was higher in FHIT-negative SSA/Ps compared with in FHIT-positive SSA/Ps (P=0.08). A total of 16.7% of EPC samples and 11.5% of SSA/Ps demonstrated a loss of MLH1/MSH2 expression, but none of the other tumor types did. P53 overexpression was significantly increased in EPC (77.8%) and CIA (60%) samples compared with in HP (0%), TSA (6.6%), SSA/P (0%) and non-serrated adenoma (10%) samples (P<0.01). These findings demonstrated that there are different expression patterns between the serrated pathway and ACS, indicating that aberrant FHIT and inhibited COX-2 expression may be associated with serrated tumorigenesis. In addition, this data indicated that EPC may contain tumors derived from the serrated pathway as well as ACS.

Frequent aberrant p53 and Fhit expression in endoscopically resected superficial hypopharyngeal cancer and esophageal cancer.

In the last decade, the incidence rate of detection rate of superficial head, neck and esophageal squamous cell carcinomas has increased with the development of endoscopic imaging techniques. These cancers are thought to arise independently subsequent to tissue exposure to a common carcinogen e.g. alcohol or tobacco. This phenomenon has been termed field cancerization. To determine the molecular background of the development of hypopharyngeal squamous cell carcinomas (HPSCCs) and double esophageal squamous cell carcinomas (DESCCs), the present study immunohistochemically assessed tumor-related protein expression [p53, Fhit (fragile histidine triad), E-cadherin and activation-induced cytidine deaminase (AID)], and subsequently determined the correlation between protein expression and clinicopathological data. Tumor specimens of 9 HPSCCs and 9 DESCCs were endoscopically obtained from 8 patients with HPSCC. The 9 DESCCs, including 5 synchronous and 4 metachronous lesions, were all obtained from four patients with HPSCC. The overexpression of p53 and loss of Fhit expression was immunohistochemically detected in 8 (88.9%) and 8 (88.9%) of the 9 HPSCCs and in 8 (88.9%) and 8 (88.9%) of the 9 DESCCs, respectively, which demonstrated the high frequency of such expression. Additionally, 7 out of 9 HPSCCs, and 7 out of 9 DESCCs demonstrated aberrant expression of p53 and Fhit. The rate of aberrant AID and E-cadherin expression was 67 and 44% in HPSCCs and 44 and 44% in DESCC, respectively. These results suggested that aberrant p53 and Fhit expression was involved in the development of HPSCC and their DESCC, and that their expression may be used for the prediction of DESCC development in patients with HPSCC, thereby acting as a biomarker of field cancerization.

Expression of methylation-modulated tumor-related genes in endoscopically resected early esophageal squamous neoplasia.

Smoking and alcohol consumption are major risk factors for the development of esophageal squamous cell carcinoma (ESCC). Recent studies have demonstrated that smoking and alcohol consumption may be associated with altered DNA methylation in human cancer development. The aim of the present study was to evaluate methylation-modulated protein expression of tumor-related genes (TRGs) in the early stages of esophageal squamous neoplasia (ESN). ESN tissue samples (n=141) comprising 19 cases of low-grade intraepithelial neoplasia (LGIN), 70 of high-grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 52 of invasive cancer, were endoscopically resected. The methylation-modulated protein expression of 5 TRGs [fragile histidine triad (FHIT), E-cadherin, MutL homolog 1 (MLH1) /MutS homolog 2 (MSH2) and cyclooxygenase-2 (COX-2)] as well as p53 was examined with immunohistochemistry, and their expression was compared with patient clinicopathological characteristics. Reduced or loss of FHIT, E-cadherin, MLH1/MSH2 and COX-2 expression was detected in 26.3 (5/19), 5.3 (1/19), 0 (0/19) and 63.2% (12/19) of LGIN cases, 61.4 (43/70), 18.6 (13/70), 7.1 (5/70) and 65.7% (46/70) of HGIN/CIS cases, and 78.8 (41/52), 50.0 (26/52), 11.5 (6/52) and 59.6% (31/52) of invasive cancer cases, respectively. Reduced or absent expression of FHIT and E-cadherin was significantly associated with neoplastic progression (FHIT, P=0.0007; E-cadherin, P=0.00014). The mean number of TRGs (FHIT, E-cadherin, MLH1/MSH2, and COX-2) that exhibited reduced or absent expression in LGIN, HGIN/CIS and invasive cancer specimens was 1.12±0.61, 1.66±0.93 and 2.09±0.96, respectively, demonstrating a significant stepwise increment from LGIN to HGIN/CIS and then to invasive cancer (P<0.05). p53 overexpression was frequently detected in ESN with head and neck carcinomas. However p53 overexpression was not significantly associated with ESN progression. An increase in the number of the 5 TRG proteins with reduced or loss of expression in the early stages of esophageal tumorigenesis was demonstrated, and their decreased expression was observed to be associated with tumor progression. Therefore, smoking and alcohol drinking may be associated with not only carcinogenesis but also the progression of ESN.

AID, p53 and MLH1 expression in early gastric neoplasms and the correlation with the background mucosa.

A number of tumor-associated genes have been associated with gastric cancer development. The present study evaluated differences in tumor-associated protein expression and phenotype among early gastric neoplasms, and correlated these data with those of the background mucosa. The expression of activation-induced cytidine deaminase (AID), p53 and MLH1 in 151 early gastric neoplasms [22 gastric adenomas, 92 intramucosal carcinomas (MCs), and 37 submucosal carcinomas (SMCs)] was examined immunohistochemically and compared with that of the corresponding background mucosal condition. The cellular phenotypes of the neoplasms and the corresponding background intestinal metaplasia were also determined. Aberrant AID, p53 and MLH1 expression was detected in 36.4, 0 and 0% of the adenomas, in 35.9, 32.6 and 16.3% of the MCs, and in 56.8, 62.2 and 21.6% of the SMCs, respectively. The frequency of aberrant AID and p53 expression in the SMCs was significantly increased compared with that in the MCs (AID, P<0.05; p53, P<0.01). Aberrant AID expression was significantly associated with p53 overexpression in the SMCs (P<0.01), but not in the adenomas or MCs. In addition, AID expression was associated with the severity of mononuclear cell activity in the non-cancerous mucosa adjacent to the tumor (P<0.05), particularly in the SMC cases. The percentage of MCs (34.8%) and SMCs (24.3%) that were of the gastric phenotype was higher compared with the percentage of adenomas (18.2%). These results indicated that p53 and MLH1 expression and a gastric phenotype may be important for carcinogenesis, and that chronic inflammation and AID and p53 expression are associated with submucosal progression.

Participation of thioredoxin in the V(V)-reduction reaction by Vanabin2.

BACKGROUND: It is well-understood that ascidians accumulate high levels of vanadium, a reduced form of V(III), in an extremely acidic vacuole in their blood cells. Vanabins are small cysteine-rich proteins that have been identified only from vanadium-rich ascidians. A previous study revealed that Vanabin2 can act as a V(V)-reductase in the glutathione cascade. METHODS: AsTrx1, a thioredoxin gene, was cloned from the vanadium-rich ascidian, Ascidia sydneiensis samea, by PCR. AsTrx1 and Vanabin2 were prepared as recombinant proteins, and V(V)-reduction by Vanabin2 was assessed by ESR and ion-exchange column chromatography. Site-directed mutagenesis was performed to examine the direct involvement of cysteine residues. Tissue expression of AsTrx1 was also examined by RT-PCR. RESULTS: When reduced AsTrx1 and Vanabin2 were combined, Vanabin2 adopted an SS/SH intermediate structure while V(V) was reduced to V(IV). The loss of cysteine residues in either Vanabin2 or AsTrx1 caused a significant loss of reductase activity. Vapp and Kapp values for Vanabin2-catalyzed V(V)-reduction in the thioredoxin cascade were 0.066mol-V(IV)/min/mol-Vanabin2 and 0.19mM, respectively. The Kapp value was 2.7-fold lower than that observed in the glutathione cascade. The AsTrx1 gene was expressed at a very high level in blood cells, in which Vanabins 1-4 were co-expressed. CONCLUSIONS: AsTrx1 may contribute to a significant part of the redox cascade for V(V)-reduction by Vanabin2 in the cytoplasm of vanadocytes, but prevails only at low V(V) concentrations. GENERAL SIGNIFICANCE: This study is the first to report the reduction of V(V) in the thioredoxin cascade.

Histological growth pattern of and alpha-actinin-4 expression in thyroid cancer.

AIM: To assess the clinicopathological significance of the histological growth pattern (HGP) and α-actinin-4 (ACTN4) expression in thyroid cancer. PATIENTS AND METHODS: We classified 83 thyroid cancer cases into infiltrative margin (IM) and pushing margin (PM) groups according to peripheral tumor margin contour and immunohistochemically determined ACTN4 expression. Correlations between clinical stage and clinicopathological characteristics were analyzed. RESULTS: IM and high ACTN4 expression were observed in 39% and 49% of cancer cases, respectively. Higher clinical stage was significantly correlated with older age, higher T and N factor, preoperative recurrent laryngeal nerve paralysis (pre-RLNP), IM, and poor prognosis. Patients with stage IV disease had significantly poorer prognosis than those with stages I-III. On multivariate analysis, older age, pre-RLNP, and IM correlated with higher clinical stages. IM was significantly correlated with high ACTN4 expression. CONCLUSION: IM, pre-RLNP, and ACTN4 expression could be novel indicators of tumor aggression and prognostic factors of thyroid cancer.

Allelotyping analysis suggesting a consecutive progression from intratubular germ cell neoplasia to seminoma and then to embryonal carcinoma of the adult testis.

Among adult testicular germ cell tumors, the pathogenesis of embryonal carcinoma remains a matter of debate. Some studies suggest a single consecutive progression from intratubular germ cell neoplasia, unclassified (IGCNU), to seminoma and then to embryonal carcinoma; others suggest that seminoma and embryonal carcinoma derive independently from IGCNU. This allelotyping study aimed to clarify the genetic relationship between embryonal carcinoma components and coexisting seminoma and/or IGCNU components. From a cohort of 18 patients with embryonal carcinoma, 11 coexisting seminoma components and 14 coexisting IGCNUs were identified. DNA isolated from each laser-microdissected tissue was subjected to polymerase chain reaction and loss of heterozygosity (LOH) analysis, using 20 polymorphic markers located on 12 chromosome arms (3q, 5q, 6p, 9p, 10q, 11p, 12p, 12q, 13q, 17p, 17q, and 18q). The concordance rate for allelic patterns was 82% between IGCNU and the coexisting seminoma components, 71% between IGCNU and the coexisting embryonal carcinoma components, and 80% between seminoma components and the coexisting embryonal carcinoma components. Estimation of probability indicated that these events were very unlikely to have occurred by chance. The total frequency of LOH increased progressively from IGCNU to seminoma and then to embryonal carcinoma, with statistically significant differences. In 7 cases with 3 histologic components, 28 chromosomal loci that showed LOH in the seminoma and embryonal carcinoma components were identified, and 15 (54%) retained heterozygosity in the coexisting IGCNUs. These findings suggest that a consecutive progression from IGCNU to seminoma, and ultimately, to embryonal carcinoma mainly occurred in the testicular germ cell tumor cases.

Metal ion selectivity of the vanadium(V)-reductase Vanabin2.

In a previous study, Vanabin2, a member of a family of V(IV)-binding proteins, or Vanabins, was shown to act as a V(V)-reductase. The current study assesses the ability of Vanabin2 to reduce various transition metal ions in vitro. An NADPH-coupled oxidation assay yielded no evidence of reduction activity with the hexavalent transition metal anions, Mo(VI)O4(2-) and W(VI)O4(2-), or with three divalent cations, Mn(II), Ni(II), and Co(II). Although Cu(II) is readily reduced by glutathione and is gradually oxidized in air, this process was not affected by the presence of Vanabin2. In the experiments conducted thus far, Vanabin2 acts only as a V(V)-reductase. This high selectivity may account for the metal ion selectivity of vanadium accumulation in ascidians.

Altered expression of p27(Kip1) -interacting cell-cycle regulators in the adult testicular germ cell tumors: potential role in tumor development and histological progression.

We examined the potential role of cell-cycle dysregulation in the development and histological progression of adult testicular germ cell tumors (TGCTs). Expressions of p27(Kip1) -interacting cell-cycle regulators (down-regulation of p27(Kip1) and overexpression of Skp2, Cks1, cyclin A, and cyclin E) and Ki-67 labeling index (LI) were immunohistochemically examined in histological components of 50 intratubular germ cell neoplasms, unclassified (IGCNUs); 74 seminomas; and 25 embryonal carcinomas, identified from 88 patients. Altered expression of p27(Kip1) , Skp2, Cks1, cyclin A, and cyclin E was observed in 20%, 12%, 16%, 10%, and 24% of IGCNUs; 26%, 36%, 27%, 89%, and 23% of seminomas; and 48%, 68%, 56%, 100%, and 60% of embryonal carcinomas, respectively. A significant difference in the frequency of Skp2 and cyclin A overexpression was observed between IGCNUs and seminomas. Significantly more frequent alterations of Skp2, Cks1, and cyclin E and p27(Kip1) were detected in embryonal carcinomas than in seminomas. Alterations of all cell-cycle regulators were significantly more frequent in embryonal carcinomas than in IGCNUs. The mean Ki-67 LI significantly increased from IGCNU (21.2%) through seminoma (34.7%) to embryonal carcinoma (54.2%). These results suggest that alterations of the p27(Kip1) -interacting cell-cycle regulators are common in TGCTs and may be involved in their histological progression.

[Acute tumor lysis syndrome in the setting of advanced gastric cancer].

A 69-year-old man was admitted with right flank pain. The patient was diagnosed with advanced gastric cancer with multiple metastases in the liver and abdominal lymph nodes and underwent chemotherapy. Three days following the initial administration of S-1 plus cisplatin, the patient developed tumor lysis syndrome (TLS) with increased LDH, hyperuricemia, hyperkalemia, and elevated creatinine. Although rare, TLS following chemotherapy for solid tumors is a potentially fatal complication, and high physician awareness is required, especially in patients with risk factors, such as bulky disease.

Loss of heterozygosity on chromosome 16q suggests malignancy in core needle biopsy specimens of intraductal papillary breast lesions.

It is often difficult to make a definitive diagnosis of papillary breast lesions using core needle biopsy (CNB) specimens. We studied loss of heterozygosity (LOH) on chromosome 16q in order to assess its diagnostic use for papillary breast lesions in CNB specimens. Of 25 patients with intraductal papillary breast tumors, we extracted DNA from paired samples of tumor cells from CNB specimens and non-tumor cells from subsequent excision specimens and analyzed LOH at the D16S419 and D16S514 loci on chromosome 16q. LOH analysis results were compared with final diagnoses based on pathological features of the resected specimens. On the CNB specimens, 21 tumors were histologically diagnosed as indeterminate or suspicious for malignancy, while four tumors were unambiguously malignant. Of the 21 indeterminate or suspicious tumors, 11 were finally diagnosed as benign and ten as malignant, and on these, LOH analyses were informative for 8 of the 11 benign tumors and 7 of the 10 malignant tumors. LOH was also informative on two of the four tumors unambiguously malignant on CNB. None of the eight informative benign tumors showed LOH on 16q. Six of the eleven informative malignant tumors showed LOH on 16q. LOH on 16q was significantly different between CNB specimens of benign and malignant intraductal papillary tumors (P = 0.007). Analysis of LOH on 16q may be helpful in making a definitive diagnosis in cases of papillary breast lesions, in both excised and CNB specimens.