Evidence for X(3872)→J/ψπ

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e^{+}e^{-}→e^{+}e^{-}J/ψπ^{+}π^{-}, using 825 fb^{-1} of data collected by the Belle detector operated at the KEKB e^{+}e^{-} collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ[over ˜]_{γγ}B(X(3872)→J/ψπ^{+}π^{-}) assuming the Q^{2} dependence predicted by a cc[over ¯] meson model, where -Q^{2} is the invariant mass squared of the virtual photon. No X(3915)→J/ψπ^{+}π^{-} candidates are found.

Anti-PD1 checkpoint inhibitor therapy in acral melanoma: a multicenter study of 193 Japanese patients.

BACKGROUND: Acral melanoma (AM) is an epidemiologically and molecularly distinct entity that is underrepresented in clinical trials on immunotherapy in melanoma. We aimed to analyze the efficacy of anti-programmed cell death 1 (anti-PD-1) antibodies in advanced AM. PATIENTS AND METHODS: We retrospectively evaluated unresectable stage III or stage IV AM patients treated with an anti-PD-1 antibody in any line at 21 Japanese institutions between 2014 and 2018. The clinicobiologic characteristics, objective response rate (ORR, RECIST), survival estimated using Kaplan-Meier analysis, and toxicity (Common Terminology Criteria for Adverse Events 4.0.) were analyzed to estimate the efficacy of the anti-PD-1 antibodies. RESULTS: In total, 193 patients (nail apparatus, 70; palm and sole, 123) were included in the study. Anti-PD-1 antibody was used as first-line therapy in 143 patients (74.1%). Baseline lactate dehydrogenase (LDH) was within the normal concentration in 102 patients (52.8%). The ORR of all patients was 16.6% (complete response, 3.1%; partial response, 13.5%), and the median overall survival (OS) was 18.1 months. Normal LDH concentrations showed a significantly stronger association with better OS than abnormal concentrations (median OS 24.9 versus 10.7 months; P < 0.001). Although baseline characteristics were similar between the nail apparatus and the palm and sole groups, ORR was significantly lower in the nail apparatus group [6/70 patients (8.6%) versus 26/123 patients (21.1%); P = 0.026]. Moreover, the median OS in this group was significantly poorer (12.8 versus 22.3 months; P = 0.03). CONCLUSIONS: Anti-PD-1 antibodies have limited efficacy in AM patients. Notably, patients with nail apparatus melanoma had poorer response and survival, making nail apparatus melanoma a strong candidate for further research on the efficacy of novel combination therapies with immune checkpoint inhibitors.

2-mm surgical margins are adequate for most basal cell carcinomas in Japanese: a retrospective multicentre study on 1000 basal cell carcinomas.

BACKGROUND: Surgery is the gold standard for basal cell carcinomas (BCC). Current recommended surgical margins for BCCs are determined from studies in Caucasian populations. However, the appropriate surgical margins for BCCs in non-white races are unclear. OBJECTIVES: To investigate the accuracy of preoperative determination of clinical tumour borders and appropriate surgical margins in Japanese patients with BCC. METHODS: The maximum calculated differences in distance between the preoperatively determined surgical margins and the actual histologic tumour side margins were considered as 'accuracy gaps' of clinical tumour borders. Estimated side margin positivity rates (ESMPRs) with narrower (2 and 3 mm) surgical margins were calculated on the basis of the accuracy gaps. RESULTS: Overall, 1000 surgically excised BCCs from 980 Japanese patients were included. The most frequent histologic subtype was nodular BCC (67%). The median accuracy gap was 0.3 mm [interquartile range (IQR): -0.5 to +1 mm]. The ESMPRs with 2- and 3-mm surgical margins were 3.8% and 1.4%, respectively. Only the ESMPRs between the well-defined (n = 921) and poorly defined clinical tumour border groups (n = 79) showed statistical difference [2-mm margin: 3.1% vs. 11.7%, OR: 3.89, 95% confidential interval (CI): 1.41-10.71, P <0.01; 3-mm margin: 0.97% vs. 6.3%, OR: 6.58, 95% CI: 1.67-25.99, P <0.01]. No significant differences in ESMPRs were noted in other subgroups including risk classifications. CONCLUSIONS: The determined clinical tumour border accuracy gaps in this Japanese cohort were negligible. Dermatologic surgeons may use narrower surgical margins with acceptable margin positivity rates. The clarity of clinical tumour borders could be an appropriate guide for selection of different surgical margins in the Japanese cohort.

Acral lentiginous melanoma: a skin cancer with unfavourable prognostic features. A study of the German central malignant melanoma registry (CMMR) in 2050 patients.

BACKGROUND: Acral lentiginous melanoma (ALM) is one of the four major subtypes in cutaneous melanoma (CM). Although ALM has a poorer prognosis than other CM subtypes, the prognostic factors associated with ALM have only been verified in small-sized cohorts because of the low incidence of ALM worldwide. OBJECTIVES: To investigate the clinical characteristics of ALM and to evaluate their prognostic values based on a large dataset from the Central Malignant Melanoma Registry (CMMR) of the German Dermatologic Society. METHODS: The Kaplan-Meier method was used to estimate the potential influence of clinical and histological parameters on ALM disease-specific survival (DSS) curves, which were compared using the log-rank test. A Cox proportional hazards model was used to identify independent prognostic factors for DSS. RESULTS: In total, 2050 patients with ALM were identified from 58 949 patients with CM recorded by the CMMR with follow-up data. In multivariate analyses, age (P = 0·006), ulceration (P = 0·013), tumour thickness (P < 0·001) and tumour spread (P < 0·001) turned out to be significant prognostic factors for DSS in ALM whereas sex, nevus association and level of invasion were not independent factors. CONCLUSIONS: ALM has the same prognostic factors as other subtypes of melanoma. Unfavourable prognosis probably derives from the delay in diagnosis in comparison with other melanoma subtypes.

Anti-PD-1 antibody monotherapy versus anti-PD-1 plus anti-CTLA-4 combination therapy as first-line immunotherapy in unresectable or metastatic mucosal melanoma: a retrospective, multicenter study of 329 Japanese cases (JMAC study).

BACKGROUND: Anti-programmed cell death protein 1 (PD-1) antibody monotherapy (PD1) has led to favorable responses in advanced non-acral cutaneous melanoma among Caucasian populations; however, recent studies suggest that this therapy has limited efficacy in mucosal melanoma (MCM). Thus, advanced MCM patients are candidates for PD1 plus anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) combination therapy (PD1 + CTLA4). Data on the efficacy of immunotherapy in MCM, however, are limited. We aimed to compare the efficacies of PD1 and PD1 + CTLA4 in Japanese advanced MCM patients. PATIENTS AND METHODS: We retrospectively assessed advanced MCM patients treated with PD1 or PD1 + CTLA4 at 24 Japanese institutions. Patient baseline characteristics, clinical responses (RECIST), progression-free survival (PFS), and overall survival (OS) were estimated using Kaplan-Meier analysis, and toxicity was assessed to estimate the efficacy and safety of PD1 and PD1 + CTLA4. RESULTS: Altogether, 329 patients with advanced MCM were included in this study. PD1 and PD1 + CTLA4 were used in 263 and 66 patients, respectively. Baseline characteristics were similar between both treatment groups, except for age (median age 71 versus 65 years; P < 0.001). No significant differences were observed between the PD1 and PD1 + CTLA4 groups with respect to objective response rate (26% versus 29%; P = 0.26) or PFS and OS (median PFS 5.9 months versus 6.8 months; P = 0.55, median OS 20.4 months versus 20.1 months; P = 0.55). Cox multivariate survival analysis revealed that PD1 + CTLA4 did not prolong PFS and OS (PFS: hazard ratio 0.83, 95% confidence interval 0.58-1.19, P = 0.30; OS: HR 0.89, 95% confidence interval 0.57-1.38, P = 0.59). The rate of ≥grade 3 immune-related adverse events was higher in the PD1 + CTLA4 group than in the PD1 group (53% versus 17%; P < 0.001). CONCLUSIONS: First-line PD1 + CTLA4 demonstrated comparable clinical efficacy to PD1 in Japanese MCM patients, but with a higher rate of immune-related adverse events.

Recurrent Aphthous Stomatitis Caused by Cytomegalovirus, Herpes Simplex Virus, and Candida Species in a Kidney Transplant Recipient: A Case Report.

Recipients of organ transplants are immunosuppressed and at high risk of oral infection. Oral diseases are often neglected compared with infections of other organs that typically confer higher morbidity. However, severe local symptoms hinder oral intake, decrease quality of life, and are sometimes lethal. Here we describe a case of a 57-year-old woman who developed recurrent aphthous stomatitis after kidney transplantation; the cause of the infection was complex and included cytomegalovirus, herpes simplex virus, and Candida species. Since misdiagnosis of oral diseases impairs patient quality of life and increases morbidity, clinicians should be aware of possible etiologies of oral infections in renal transplant recipients.

Exploration of immobilization conditions of cellulosic lyotropic liquid crystals in monomeric solvents by in situ polymerization and achievement of dual mechanochromism at room temperature.

We investigated conditions to prepare cellulosic cholesteric liquid crystalline (ChLC) films in order to accomplish dual mechanochromism, i.e., colour control and circular dichroic inversion upon mechanical stimulus, at room temperature. Flexible propionylated hydroxypropyl cellulose (PHPC) was prepared by a simple reaction and found to be capable of forming lyotropic ChLC in various monomeric solvents. The ChLC solutions were subjected to in situ polymerization to obtain PHPC/synthetic polymer composite films incorporating the ChLC structure. However, the immobilization behaviour depended on the type of original monomers. Differential scanning calorimetry and solid-state NMR measurement revealed that the ChLC structure was more highly fixed when the compatibility between PHPC and the coexisting polymers was lower. Eventually, thus obtained ChLC composite films exhibited dual mechanochromism under ambient temperature.

Detection of novel murine mammary tumor viruses by interspecies immunoassays.

Radioimmunoassays were developed that can detect antigenic determinants common to mammary tumor viruses (MTV's) of four distinct Mus species: M. musculus, M. cervicolor, M. cookll, and M. caroll. The radioimmunoassays were based on the immunologic cross-reactivity observed between the murine mammary tumor viruses (MuMTV) of M. musculus and type B retrovirus isolated from M. cervicolor. Both of the glycoproteins of MuMTV (gp52, gp36) shared antigenic determinants with virions of M. cervicolor mammary tumor virus. Interspecies radioimmunoassays for gp52 and gp36 were developed and used to detect viruses in the milk of noninbred feral Mus species and MuMTV-related translational products in mammary tumors in these species. Type C and type D retroviruses, as well as the M432 retrovirus of M. cervicolor, did not react in either assay. Both interspecies immunoassays were therefore specific for the detection of distinct MuMTV-related antigenic determinants.

Characterization of a new virus from Mus cervicolor immunologically related to the mouse mammary tumor virus.

A virus, similar to the murine mammary tumor viruses (MuMTV) of the laboratory mouse Mus musculus, was identified in the milk of M. cervicolor popaeus mice. The virus was morphologically indistinguishable from the type-B MuMTV and was thus termed MC-MTV. Radioimmunoassays for the 52,000-dalton major envelope glycoprotein and the 28,000-dalton major internal protein of MuMTV demonstrated that MC-MTV shared some antigenic determinants with both of these MuMTV proteins. This reactivity was clearly different, however, from that observed with all MuMTV tested from M. musculus. MC-MTV had a density of 1.16 g/ml in sucrose and a virion-associated DNA polymerase with a divalent cation preference for Mg2+ over Mn2+. Radioimmunoassays clearly differentiated MC-MTV from the other viruses previously identified from M. cervicolor, i.e., M432, CERV-CI, and CERV-CII. These studies thus identified the first virus from another species that is immunologically related to the MuMTV of M. musculus. Particles similar to MC-MTV were also observed in a spontaneous M. cervicolor popaeus mammary tumor.

Indirect leukocyte migration inhibition in breast cancer and benign breast disease patients by mouse mammary tumor virus grown in feline kidney cells.

Indirect migration inhibition assays were performed with normal and mammary tumor-bearing C3H/HeN mice and patients with breast disease to assess cellular immunity against three different mouse mammary tumor virus (MTV) preparations grown in feline kidney cell cultures and against a mouse-derived MTV preparation. MTV obtained after passage through feline kidney cells and the mouse-derived MTV were capable of eliciting macrophage migration inhibitory factor production by mouse spleen cells obtained from normal or mammary tumor-bearing C3H/HeN mice, thus demonstrating a similar degree of antigenicity of these preparations. In experiments with human breast cancer patients' leukocytes, leukocyte inhibitory factor (LIF) was produced by 32-50% of these patients in response to the mouse-derived MTV or to three different MTV preparations obtained after passage through feline kidney cells. A significant proportion (31-54%) of benign breast disease patients also reacted with both the mouse-derived and feline-derived MTV preparations. Patients with both malignant and benign breast disease, however, had a significantly different (P less than .05) pattern of reactivity to mouse- and feline-derived MTV preparations from that observed with normal donors. Finally, some LIF activity was also observed (but not statistically significant with the use of nonparametric analysis methods) when feline leukemia virus was used as antigen with these patients. The data suggest that both breast cancer and benign breast disease patients were reactive against antigens largely specific for MTV in the feline cells and, presumably, were not reactive against feline cellular components, although the second possibility cannot be completely ruled out.

Radioimmunoassays that demonstrate type-specific and group-specific antigenic reactivities for the major internal structural protein of murine mammary tumor viruses.

The 28,000-dalton (p28) major structural polypeptide of the mouse mammary tumor virus (MMTV) was isolated and used to develop a highly sensitive and specific radioimmunoassay. Under conditions of limiting antibody in competitive binding assays, as little as 50 pg of purified p28, as well as disrupted MMTV virions and mammary tumor extracts, competed specifically with 125I-labeled MMTV p28. The p28 polypeptide was further shown to contain both group-specific and type-specific antigenic determinants, thus also allowing for further differentiation of various MMTV strains.

Use of monoclonal antibodies to define the diversity of mammary tumor viral gene products in virions and mammary tumors of the genus Mus.

Monoclonal antibodies have been generated against disrupted mammary tumor viruses isolated from Mus musculus, Mus cervicolor, and Mus cookii. Monoclonal antibodies directed against the M.W. 36,000 external glycoproteins of these viruses demonstrate the presence of multiple epitopes, i.e., distinct antigenic determinants, within these glycoproteins. These epitopes represent type, group, and interspecies determinants. Monoclonal antibodies have also been used to define multiple epitopes on the M.W. 28,000 major internal polypeptides of murine mammary tumor viruses that exhibit both type- and group-specific determinants. The monoclonal antibodies to the M.W. 36,000 glycoprotein and the M.W. 28,000 polypeptide have been used to distinguish all six mammary tumor virus isolates of M. musculus from each other, including both endogenous and exogenous viruses from the same strain, and a new virus isolate from BALB/c mice. With the use of the immunoperoxidase technique, the monoclonal antibodies generated have been used to demonstrate a heterogeneity of expression of mammary tumor virus gene products in primary mammary tumors of three Mus species. These studies have revealed that a given antigenic determinant may be expressed differentially in mammary tumors of two different Mus species, among mammary tumors of the same Mus species, and, at times, in different areas of the same mammary tumor.

Mammary tumorigenesis and tumor morphology in four C3H sublines with or without exogenous mammary tumor virus.

Mammary tumorigenesis was surveyed in retired breeding females in four sublines of the C3H strain: in standard milk-transmitted early oncogenic mouse mammary tumor virus (MMTV)-infected C3H/He and C3H/Ki mice, and in standard milk-transmitted early oncogenic MMTV free C3Hf/He and C3Hf/Ki mice. All of 58 C3H/Ki mice and 98% (306 of 309) of the C3H/He mice developed palpable mammary tumors at average ages of 276 and 284 days, respectively. Thirty-one % (47 of 152) of the C3Hf/Ki mice and 77% (168 of 218) of the C3Hf/He mice developed palpable mammary tumors at average ages of 798 and 757 days, respectively. The mammary tumors removed from C3H/He and C3H/Ki mice were all adenocarcinomas of epithelial origin, and all contained MMTV. The mammary tumors removed from C3Hf/He and C3Hf/Ki mice were either adenocarcinomas or sarcomas. The carcinomas were of epithelial origin and all expressed the late oncogenic endogenous MMTV. The sarcomas were of histiocyte or fibrocyte origin and contained neither virus particles nor MMTV antigenic markers. It is concluded that exogenous standard milk-transmitted oncogenic MMTV oncogenesis in C3H mice is not modified by host genetic factors. In contrast, late oncogenic endogenous MMTV oncogenesis is influenced both by host genetic control of the expression of the late oncogenic MMTV provirus and by the location of the proviral genes in the germline DNA.

Characterization of mouse mammary tumor viruses propagated in heterologous cells.

Mouse mammary tumor viruses (MMTV) from three different strains of mice have been used to establish productive infections in feline and mink cell lines. The virions that are released by these cells compete completely in a radioimmunoassay for the major virion surface glycoprotein of MMTV (gp52), thus demonstrating that antigenic determinants of gp52 are viral coded. Competitive molecular hybridization studies have shown that the 60 to 70 S RNA's of MMTV's propagated in feline cells contain all the nucleic acid sequences found in 60 to 70 S RNA from MMTV synthesized by murine cells. The virion buoyant densities in sucrose and cesium chloride, virion sedimentation coefficient, divalent cation requirement of the virion DNA polymerase, and morphology of MMTV's synthesized in heterologous cells are similar to those of MMTV's grown in murine cells. Cultures of MMTV-infected feline cells have continuously released between 0.1 and 1.0 microgram of virus per 10(7) cells (75-sq cm flask) per day during the 60-week observation period. No detectable feline or murine type C viruses were produced by these cultures.

Elevated serum c-erbB-2 antigen levels and decreased response to hormone therapy of breast cancer.

PURPOSE: Decisions concerning the use of hormone therapy to treat metastatic breast cancer are made on the basis of the presence of estrogen receptor (ER). Despite the presence of ER, half of patients will not respond to hormone treatment. The purpose of this study was to determine the effect of overexpression of HER-2/neu on the response to hormone therapy. PATIENTS AND METHODS: Sera from 300 metastatic breast cancer patients with ER-positive (ER+), ER status unknown, or ER-/progesterone receptor-positive (PR+) randomized to receive second-line hormone therapy with either megestrol acetate or fadrozole were evaluated. An enzyme immunoassay (EIA) specific for the extracellular domain of the c-erbB-2 (HER-2/neu) oncogene product was used to detect serum levels. RESULTS: Fifty-eight patients (19.3%) had elevated serum c-erbB-2 protein levels, using a selected cut-point of 30 U/mL. The response rate (complete responses [CRs] plus partial responses [PRs] plus stable disease [S]) to endocrine therapy was 40.9% in 242 patients with low serum c-erbB-2 levels and only 20.7% in 58 patients with elevated serum c-erbB-2 levels (P = .004). The median duration of treatment response was longer in the group with low serum c-erbB-2 levels (15.5 months) compared with the group with elevated serum c-erbB-2 levels (11.6 months). Survival was also significantly shorter in patients with elevated serum c-erbB-2 levels (P < .0001). CONCLUSION: Patients with ER+/c-erbB-2+ metastatic breast cancer are less likely to respond to hormone treatment than ER+/c-erbB-2- patients. Their survival duration is also shorter.

Elevated soluble c-erbB-2 antigen levels in the serum and effusions of a proportion of breast cancer patients.

PURPOSE: An enzyme-linked immunosorbent assay (ELISA) for the extracellular domain of the c-erbB-2 oncogene product was developed and evaluated to determine if soluble c-erbB-2 could be detected in the serum and effusions of cancer patients. PATIENTS AND METHODS: Sera from 208 previously untreated or progressing cancer patients and 69 healthy controls were assayed in a double-antibody sandwich ELISA that used two monoclonal antibodies to the native extracellular domain of the c-erbB-2 receptor. Fisher's exact test was used to analyze the statistical significance of the frequency of elevated serum c-erbB-2 levels. Immunoprecipitation and Western blotting were used to characterize further the c-erbB-2 immunoreactivity in the serum of four breast cancer patients. RESULTS: Sera from 12 of 53 patients (23%) with metastatic or locally advanced breast cancer, zero of 69 controls, one of 31 patients with ovarian cancer (3%), and two of 124 other cancer patients (2%) had soluble c-erbB-2 values greater than or equal to 5 U/mL. The number of breast cancer patients with elevated serum c-erbB-2 levels was significantly greater than that of the control group (P less than .0001), the ovarian cancer group (P less than .03), and the other cancers group (P less than .0001). Also, two of five effusions (40%) from breast cancer patients had an elevated soluble c-erbB-2 antigen level, compared with zero of 17 effusions from patients with benign diseases. Western blotting of four sera from breast cancer patients with elevated serum c-erbB-2 antigen levels produced bands of approximately 105 kD that seemed to correlate in intensity with increasing ELISA serum levels. CONCLUSION: Serum c-erbB-2 levels are elevated in approximately one fourth of patients with locally advanced or metastatic breast cancer.

LANGUAGE DEVELOPMENT. The developmental dynamics of marmoset monkey vocal production.

Human vocal development occurs through two parallel interactive processes that transform infant cries into more mature vocalizations, such as cooing sounds and babbling. First, natural categories of sounds change as the vocal apparatus matures. Second, parental vocal feedback sensitizes infants to certain features of those sounds, and the sounds are modified accordingly. Paradoxically, our closest living ancestors, nonhuman primates, are thought to undergo few or no production-related acoustic changes during development, and any such changes are thought to be impervious to social feedback. Using early and dense sampling, quantitative tracking of acoustic changes, and biomechanical modeling, we showed that vocalizations in infant marmoset monkeys undergo dramatic changes that cannot be solely attributed to simple consequences of growth. Using parental interaction experiments, we found that contingent parental feedback influences the rate of vocal development. These findings overturn decades-old ideas about primate vocalizations and show that marmoset monkeys are a compelling model system for early vocal development in humans.

Tissue and serum c-erbB-2 and tissue EGFR in breast carcinoma: three years follow-up.

Amplification of erbB-1 and c-erbB-2 genes has been shown in human breast cancer. Expression of these protooncogenes results in production of epidermal growth factor receptor (EGFR) and c-erbB-2. Both are transmembrane receptors with tyrosine kinase activity. Recent data have indicated that the external domain of c-erbB-2 is shed into the culture supernatant of certain breast cancer cell lines and sera of breast cancer patients. A body of literature has shown that the overexpression of these receptors in malignant tissue and c-erbB-2 when shed into serum is associated with bad prognosis. In the present work, tissue EGFR and c-erbB-2 were determined in the membrane fractions of histopathologically verified malignant and normal tissues from the same breast of 94 patients. These values were also determined in 48 tissue specimens of benign mastopathies. Serum c-erbB-2 was quantified in breast cancer patients (n = 105), patients with benign breast disease (n = 48) and 30 apparently healthy women as controls. Patients were followed up by determination of serum c-erbB-2 for one year and clinically for three years to detect any distant metastasis or recurrence. The levels of tissue and serum c-erbB-2 and Estrogen receptors were significantly higher in the carcinomas and sera of breast cancer patients than benign breast diseases or normal controls. Follow-up, although short, of pre-operative serum c-erbB-2 showed a prognostic value (P = 0.007) better than that of tumor size (P = 0.04), EGFR (P = 0.18), nodal involvement (P = 0.25) and tissue c-erbB-2 (P = 0.85). The shedding of soluble fragments of c-erbB-2 into the serum seems to be a characteristic of the potentially malignant cell. The EGFR mean level, however, was significantly lower in malignant tissues than benign and normal ones. A new definition of EGFR status was developed. Accordingly, the recurrence of the disease was more frequent among patients with negative EGFR. The present work did not reveal any correlation between tissue, serum c-erbB-2 or EGFR on one hand and age, menopausal status, stage, histological type and grade of carcinomas and nodal involvement on the other hand. The present work showed an inverse correlation between estrogen receptor level and level of EGFR in malignant tissues.

Bone morphogenetic protein-2 and type IV collagen expression in psammoma body forming ovarian cancer.

Psammoma bodies (PBs), characterized as calco-spherules with concentric laminations, are common in serous tumors of the ovary. However, there is no agreements as to how the PBs are formed. Bone morphogenetic protein-2 (BMP-2) has recently been proposed to be involved in the calcification of tumor cells and recent electron microscopic studies demonstrated the presence of type IV collagen in PBs. Based on this evidence, we postulated a possibe role for BMP-2 and type IV collagen in the formation of PBs in ovarian cancer. We examined the expression of BMP-2 and typle IV collagen by immunohistochemistry and reverse transcription PCR (RT-PCR) in PBs-forming (NK-211) and -non-forming (SHIN-3, KF-1, A2780, KK-92, KOC-2S, SKOV-3, OMC-3, MN-1, EC, and KEN-3) ovarian cancer cell lines in vitro and in surgical specimens of serous adenocarcinoma (SA) with/without PBs and mucinous adenocarcinoma (MA) of the ovary. Cellular growth of cell lines was also evaluated by their doubling time in vitro. Transcripts for BMP-2 mRNA were detected by RT-PCR in all cell lines. By immunohistochemistry, BMP-2 protein expression was positive in 45% (5 out of 11) of cell lines. 36.4% (4 out of 11) were positive for type IV collagen. PBs-forming NK-211 was intensively positive for both BMP-2 and type IV collagen. In addition, NK-211 demonstrated extremely slow growth with a doubling time of 450 hours. In surgical specimens, BMP-2 vs. type IV collagen positivities in tumor cells were 100% (20 out of 20) vs. 40% (8 out of 20) in SA with PBs, 61.1% (11 out of 18) vs. 0% (0 out of 18) in SA without PBs and 75% (9 out of 12) vs. 0% (0 out of 12) in MA. In PBs themselves, 100% (20 out of 20) positivity for BMP-2 and 80% (16 out of 20) for type IV collagen was shown. These results raise the possibility that BMP-2 and type IV collagen-producing slow growing tumor cells form PBs in ovarian cancer.