Naoki Kanomata

Bone-marrow-derived myofibroblasts contribute to the cancer-induced stromal reaction.

To confirm whether human cancer-induced stromal cells are derived from bone marrow, bone marrow (BM) cells obtained from beta-galactosidase transgenic and recombination activating gene 1 (RAG-1) deficient double-mutant mice (H-2b) were transplanted into sublethally irradiated severe combined immunodeficient (SCID) mice (H-2d). The human pancreatic cancer cell line Capan-1 was subcutaneously xenotransplanted into SCID recipients and stromal formation was analyzed on day 14 and on day 28. Immunohistochemical and immunofluorescence studies revealed that BM-derived endothelial cells (X-gal/CD31 or H-2b/CD31 double-positive cells) and myofibroblasts (X-gal/alpha-smooth muscle actin or H-2b/alpha-smooth muscle actin double-positive cells) were present within and around the cancer nests. On day 14, the frequencies of BM-derived endothelial cells and BM-derived myofibroblasts were 25.3+/-4.4% and 12.7+/-9.6%, respectively. On day 28, the frequency of BM-derived endothelial cells was 26.7+/-9.7%, which was similar to the value on day 14. However, the frequency of BM-derived myofibroblasts was significantly higher (39.8+/-17.1%) on day 28 than on day 14 (P<0.05). The topoisomerase IIalpha-positive ratio was 2.2+/-1.2% for the H-2b-positive myofibroblasts, as opposed to only 0.3+/-0.4% for the H-2b-negative myofibroblasts, significant proliferative activity was observed in the BM-derived myofibroblasts (P<0.05). Our results indicate that BM-derived myofibroblasts become a major component of cancer-induced stromal cells in the later stage of tumor development.

Tumor-infiltrating lymphocytes are important pathologic predictors for neoadjuvant chemotherapy in patients with breast cancer

Neoadjuvant chemotherapy or preoperative systemic therapy is increasingly considered for patients with operable breast cancer. Patients with breast cancer were examined for pathologic factors predictive of response to neoadjuvant chemotherapy, using an anthracycline-based regimen. For clinical histomorphology and biomarkers, factors were compared among 16 pathologically complete responses and 52 nonpathologically complete responses, using univariate analysis and multivariate regression analysis of principal components, using preneoadjuvant chemotherapy needle biopsy samples as follows: degree of tumor-infiltrating lymphocytes, histologic grade, biology-based tumor type (hormone receptors and HER2 [human epidermal growth factor receptor type 2]), age, clinical TNM stage, and TNM staging. In univariate analysis, high tumor-infiltrating lymphocyte, high histologic grade, and hormone receptors(-)/HER2(+) were significantly associated with pathologically complete responses (93.7%, P < .0001; 81.3%, P = .0206; 43.7%, P = .014, respectively). In multivariate principal component regression analysis, high tumor-infiltrating lymphocytes were the best independent predictor for pathologically complete responses (odds ratio, 4.7; confidence interval, 2.2-10.06; P < .0001). Among tumor-infiltrating lymphocytes and biology-based tumor types, patients with high tumor-infiltrating lymphocytes had pathologically complete responses more than nonpathologically complete responses, especially in the hormone receptors(-)/HER2(+) group. Among high tumor-infiltrating lymphocyte cases, T lymphocytes showed more predominant tendency than B lymphocytes in the pathologically complete responses cases, compared with nonpathologically complete responses cases. These findings indicate that high tumor-infiltrating lymphocytes are important predictors of pathologically complete responses to neoadjuvant chemotherapy, especially in the hormone receptors(-)/HER2(+) group.

The role of immunohistochemistry in the differential diagnosis of breast lesions

Immunohistochemistry may be helpful in the diagnosis of various breast lesions. It can be used to assist in distinguishing benign and malignant conditions, or to clarify the histological subtype of invasive carcinomas. There are several markers relatively frequently utilised. Myoepithelial markers (p63, alpha-SMA, smooth muscle myosin heavy chain, and others) are useful to highlight myoepithelial cells. They are employed to verify myoepithelial cell lining in intraductal papillary lesions, or to recognise peripheral myoepithelial cells for non-invasive carcinoma, although their staining results are not always excellent. High molecular weight cytokeratins (CK5/6, CK14, 34betaE12) typically show a mosaic-like pattern of expression in benign papillary/hyperplastic lesions, and are mostly negative in ductal in situ carcinoma, but some exceptions exist. Neuroendocrine differentiation (confirmed by anti-chromogranin A or synaptophysin) suggests malignancy in solid and papillary intraductal epithelial proliferations. The significance of immunohistochemical evaluation of apocrine lesions is still controversial. Negative E-cadherin staining is used for making confirmative diagnosis of lobular carcinoma, with a specificity and sensitivity of approximately 90%. Cytokeratins, especially the antibody 34betaE12, are of value to differentiate spindle cell carcinoma from phyllodes tumour. There are some other useful markers for characterising certain histological subtypes. Nevertheless, for accurate diagnosis, it is essential to correlate the immmunohistochemical staining results with the histological findings.

High b Value (2,000 s/mm2) Diffusion-Weighted Magnetic Resonance Imaging in Prostate Cancer at 3 Tesla: Comparison with 1,000 s/mm2 for Tumor Conspicuity and Discrimination of Aggressiveness

Objective The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T. Materials and Methods The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm2 and 0, 2000 s/mm2) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10−3 mm2/s) of the tumor regions and normal regions were measured. Results Mean LCS and TNR at 0, 2000 s/mm2 was significantly higher than those at 0, 1000 s/mm2 (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm2 was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm2 (ρ = −0.602; p<0.001) and 0, 2000 s/mm2 (ρ = −0.645; p<0.001). Conclusions For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm2 is more useful than b = 0, 1000 s/mm2.

Vasohibin-2 Expressed in Human Serous Ovarian Adenocarcinoma Accelerates Tumor Growth by Promoting Angiogenesis

Vasohibin-1 (VASH1) is a VEGF-inducible endothelium-derived angiogenesis inhibitor and VASH2 is its homolog. Our previous analysis revealed that VASH1 is expressed in endothelial cells to terminate angiogenesis, whereas VASH2 is expressed in infiltrating mononuclear cells mobilized from bone marrow to promote angiogenesis in a mouse model of hypoxia-induced subcutaneous angiogenesis. To test the possible involvement of VASH2 in the tumor, we examined human ovarian cancer cells for the presence of VASH2. Immunohistochemical analysis revealed that VASH2 protein was preferentially detected in cancer cells of serous ovarian adenocarcinoma. We then used SKOV-3 and DISS, two representative human serous adenocarcinoma cell lines, and examined the role of VASH2 in the tumor. The knockdown of VASH2 showed little effect on the proliferation of cancer cells in vitro but notably inhibited tumor growth, peritoneal dissemination, and tumor angiogenesis in a murine xenograft model. Next, we stably transfected the human VASH2 gene into two types of murine tumor cells, EL-4 and MLTC-1, in which endogenous VASH2 was absent. When either EL-4 or MLTC-1 cells were inoculated into VASH2 (−/−) mice, the VASH2 transfectants formed bigger tumors when compared with the controls, and the tumor microvessel density was significantly increased. VASH2 stimulated the migration of endothelial cells, and its increased expression in cancer cells is related to the decrease of mir-200b. These results indicate that VASH2 expressed in serous ovarian carcinoma cells promoted tumor growth and peritoneal dissemination by promoting angiogenesis. Mol Cancer Res; 10(9); 1135–46. ©2012 AACR.

Carcinosarcoma (pure endocrine cell carcinoma with sarcoma components) of the stomach

A case of gastric carcinosarcoma with a rare histology is reported. Grossly, a huge ulcerative tumor (Borrmann type 3 tumor, measuring 10 × 6 cm) was observed on the lesser curvature side of the stomach. Microscopically, the tumor consisted of carcinoma and sarcoma components. The main tumor component consisted of an endocrine cell carcinoma exhibiting positive reactions for cytokeratins, chromogranin A, synaptophysin, and CD56. The sarcoma component occupied less than 10% of the entire tumor area and consisted of spindle cells, some of which showed a rhabdomyosarcoma differentiation. Some of the spindle cells also showed an atypical cartilage or osseous differentiation. This sarcoma component exhibited positive staining not only for vimentin and desmin, but also for cytokeratins. Transitions between these two components were occasionally observed. These findings suggest that the sarcoma component in our case most likely originates from the endocrine cell carcinoma component.

Inverse association between histologic inflammation in needle biopsy specimens and prostate cancer in men with serum PSA of 10-50 ng/mL.

OBJECTIVES To investigate the effect of the presence of histologic inflammation in needle biopsy specimens on the detection of prostate cancer (PCa) in men with a high serum prostate-specific antigen (PSA) level. METHODS This study included 143 consecutive patients with serum a PSA level of 10-50 ng/mL who had undergone initial needle biopsies of the prostate. We defined moderate or severe inflammation in the biopsy specimens, according to De Marzo et al., as the presence of histologic inflammation. RESULTS Of the 143 patients, 86 and 57 were diagnosed with PCa (PCa group) or benign prostatic disease (BPD group), respectively. The prostate volume and transition zone volume in the PCa group were significantly smaller than those in the BPD group, and the serum PSA level, PSA density (PSAD), and PSAD in the transition zone were significantly greater than those in the BPD group. A significant difference was found in the incidence of histologic inflammation between the PCa (40.7%) and BPD (73.7%) groups. Among the factors examined, the PSAD and the presence of histologic inflammation appeared to be independently associated with the detection of PCa. Furthermore, the combined consideration of these 2 independent factors could differentiate PCa from BPD in the biopsy specimens with a sensitivity, specificity, positive predictive value, and negative predictive value of 87.2%, 63.2%, 78.1%, and 76.6%, respectively. CONCLUSIONS It seems possible to avoid unnecessary repeat biopsy using the PSAD and the presence of histologic inflammation in biopsy specimens in patients with continuously elevated serum PSA levels after the initial biopsy.

Preferential antitumor effect of the Src inhibitor dasatinib associated with a decreased proportion of aldehyde dehydrogenase 1-positive cells in breast cancer cells of the basal B subtype.

BackgroundRecent studies have suggested that the Src inhibitor dasatinib preferentially inhibits the growth of breast cancer cells of the basal-like subtype. To clarify this finding and further investigate combined antitumor effects of dasatinib with cytotoxic agents, a panel of breast cancer cell lines of various subtypes was treated with dasatinib and/or chemotherapeutic agents.MethodsSeven human breast cancer cell lines were treated with dasatinib and/or seven chemotherapeutic agents. Effects of the treatments on c-Src activation, cell growth, cell cycle, apoptosis and the proportion of aldehyde dehydrogenase (ALDH) 1-positive cells were examined.ResultsThe 50%-growth inhibitory concentrations (IC50s) of dasatinib were much lower in two basal B cell lines than those in the other cell lines. The IC50s of chemotherapeutic agents were not substantially different among the cell lines. Dasatinib enhanced antitumor activity of etoposide in the basal B cell lines. Dasatinib induced a G1-S blockade with a slight apoptosis, and a combined treatment of dasatinib with etoposide also induced a G1-S blockade in the basal B cell lines. Dasatinib decreased the expression levels of phosphorylated Src in all cell lines. Interestingly, dasatinib significantly decreased the proportion of ALDH1-positive cells in the basal B cell lines but not in the other cell lines.ConclusionsThe present study indicates that dasatinib preferentially inhibits the growth of breast cancer cells of the basal B subtype associated with a significant loss of putative cancer stem cell population. A combined use of dasatinib with etoposide additively inhibits their growth. Further studies targeting breast cancers of the basal B subtype using dasatinib with cytotoxic agents are warranted.

Hyaluronan synthase expression in pleural malignant mesotheliomas

Hyaluronan (HA) is thought to play several important roles in tumor growth, tumorigenicity, and tumor dissemination and metastasis. Recently, three isoforms of hyaluronan synthase (HAS) have been cloned. Our objective was to determine which of the HAS isoforms were expressed in pleural malignant mesotheliomas, the most representative lesion of HA-producing tumors. We studied 10 cases of pleural malignant mesothelioma using novel antibodies of HAS. We compared HAS expression patterns of mesothelioma and pulmonary adenocarcinoma. Immunohistochemically, 9 of 10 (90%) cases of mesothelioma had extensive reaction to anti-HAS1 and anti-HAS2 antibodies, while HAS3 overexpression was present in 4 of 10 cases (40%). Of 20 cases of pulmonary adenocarcinoma, 5 overexpressed HAS1 (25%), 16 of 20 HAS2 (80%), and 4 of 20 HAS3 (20%). The expression level of HAS1 was significantly higher in mesotheliomas than in pulmonary adenocarcinoma (P=0.0036). Our data suggests that HAS1 might be a useful positive marker of malignant mesothelioma. However, a definitive conclusion should be based on further large-scale studies.

Usefulness of immunohistochemistry for differential diagnosis between benign and malignant breast lesions

Immunohistochemistry (IHC) is routinely performed during pathology practice for various breast lesions. Hormone receptor and HER2 analysis for primary breast carcinoma and cytokeratin staining for sentinel lymph nodes analysis are widely conducted. In addition to those markers, there are several situations in which certain IHC staining is valuable as an ancillary tool. This manuscript will present three useful examples of IHC for making differential diagnosis between benign and malignant lesions. Case 1 is an intraductal papilloma with solid epithelial proliferation, for which diagnosis was resolved by myoepithelial markers and high-molecular-weight cytokeratins (HMWCKs). Case 2 is a noninvasive ductal carcinoma with solid and papillary morphology. Many cases with such morphology mimic benign papillomas, but expression of neuroendocrine markers may lead to the correct diagnosis. Case 3 is a benign complex sclerosing lesion, with recognition of a pseudoinvasive process by myoepithelial markers. Although IHC results were excellent in these cases, they are effective only for limited situations. It is important to use IHC with caution, and re-evaluation of histological findings on hematoxylin and eosin stain and clinicopathological correlation of each case is essential.