Lymph node retrieval after colorectal cancer surgery: a comparative study of the efficacy between the conventional manual method and a new fat dissolution method

PURPOSE

This study compared the efficacy of two different methods for lymph node (LN) searching after colorectal cancer surgery: the fat dissolution and the conventional manual method.

METHODS

For the fat dissolution method, we used a commercially available solution of collagenase and lipase (FD group). The primary endpoint was the number of identified LNs in the FD group compared to an historical control (control group) after adjusting by propensity score matching.

RESULTS

Using 37 matched patients from each group, we identified 20.6 ± 7.2 LNs using the fat dissolution method compared to 13.5 ± 5.9 using the conventional method (t test, P < 0.01). Three patients in the FD group received an inappropriate LN examination in terms of number, while the number of the retrieved LNs was < 12 in 12 patients in the control group. The mean diameter of LNs without metastasis was 3.2 ± 1.9 mm in the FD group, and 40% of metastasis cases were found in LNs < 5 mm in diameter. A pathological examination confirmed that using the fat resolution method did not change the morphological or immunochemical staining findings.

CONCLUSION

We demonstrated that fat dissolution had a positive impact on the number of retrieved LNs after colorectal cancer surgery without disturbing the microscopic observation.

Measurements of radial profile of hydrogen and deuterium density in isotope mixture plasmas using bulk charge exchange spectroscopy

A bulk charge exchange spectroscopy system has been applied to measure the radial profiles of the hydrogen (H) and deuterium (D) density ratio in the isotope mixture plasma in a large helical device. Charge exchange lines of H_α and D_α are fitted by 4 Gaussian of H and D cold components and H and D hot components with 5 parameters by combining the measurement of plasma toroidal rotation velocity with carbon charge exchange spectroscopy. The radial profiles of the relative density of hydrogen and deuterium ions are derived from H and D hot components measured and the beam density calculated from beam attenuation calculation. A proof-of-principle experiment is performed by the H pellet and the D pellet injections into the H-D mixture plasma.

Abstract 4833: Antibody-drug conjugate targeting glypican-1 shows tumor growth inhibition in cholangiocarcinoma

Cholangiocarcinoma is one of the most highly malignant cancers. Many patients need systemic chemotherapy for tumor development and recurrence, but their prognosis is poor. Therefore new treatment options are urgently required. We confirmed that the expression of glypican-1 (GPC1) was enhanced in cholangiocarcinoma. GPC1 is a cell surface membrane protein and has been reported as a poor prognostic factor in pancreatic cancer. In this study, we aimed to develop a new therapy for cholangiocarcinoma by the antibody-drug conjugate (ADC) targeting GPC1. By immunohistochemical analysis, enhanced expression of GPC1 was observed in clinical specimens of cholangiocarcinoma. KKU-055 and KKU-100 cells, which are cell lines of cholangiocarcinoma, had high expression of GPC1. In the KKU-055 xenograft model when we administered fluorescently-labeled GPC1 antibody to mice, it accumulated in tumor tissue. We developed a new anti-GPC1 monoclonal antibody (mAb) with highly internalizing activity. The anti-GPC1 mAb was conjugated with the cytotoxic agent monomethyl auristatin F (MMAF). GPC1-ADC showed potent antitumor effect toward KKU-055 and KKU-100 cells compared with the control ADC. In the KKU-055 xenograft model, GPC1-ADC had significant and potent tumor growth inhibition in a dose-dependent manner. In summary, our newly-developed GPC1-ADC showed significant tumor growth inhibition against GPC1-positive cholangiocarcinoma cell lines. Our preclinical data demonstrated that targeting GPC1 by ADC is a promising therapy for GPC1-positive cholangiocarcinoma.

Citation Format: Keiichiro Yokota, Satoshi Serada, Shigehiro Tsujii, Kosuke Hiramatsu, Tsutomu Namikawa, Ichiro Murakami, Kazuhiro Hanazaki, Tetsuji Naka. Antibody-drug conjugate targeting glypican-1 shows tumor growth inhibition in cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4833.

Vocal cord inflammatory myofibroblastic tumor with mucoid deposits harboring TIMP3-ALK fusion: A potential diagnostic pitfall

A 35-year-old Japanese man who had experienced hoarseness for 10 years presented with a vocal cord lesion. A gross examination revealed a left vocal cord polyp occupying two-thirds of the vocal space. The endoscopically resected lesion contained scattered atypical fibroblastic, stellate, or ganglion-like cells with mucoid stroma. Vacuolated cells were also seen. Lymphoplasmacytic infiltrate was largely undetectable. A vocal cord polyp was first suspected, but well-differentiated liposarcoma and inflammatory myofibroblastic tumor (IMT) were included in the differential diagnoses. The tumor cells were positive for anaplastic lymphoma kinase (ALK), calponin, and vimentin, and negative for other smooth muscle markers by immunohistochemistry. Structures resembling myofibroblasts were not observed by electron microscopy, which confirmed abundant rough endoplasmic reticulum in the tumor cells and accumulated lipid droplets in some tumor cells. ALK gene rearrangement was detected by fluorescence in situ hybridization, and TIMP3-ALK fusion was confirmed by 5' rapid amplification of cDNA ends. We diagnosed the lesion as an IMT, and an ALK-rearranged stellate cell tumor may be postulated. This is the first report of a fusion partner gene of ALK in a case of laryngeal IMT.

Intrahepatic bile duct adenoma in a patient with gastric cancer

We report a case of intrahepatic bile duct adenoma (BDA) detected during laparoscopic distal gastrectomy for gastric cancer. A 70-year-old man was referred to our hospital for the treatment of gastric cancer. Esophagogastroduodenoscopy revealed an irregular, nodular, and elevated lesion on the greater curvature side of the middle third of the stomach. Abdominal contrast-enhanced computed tomography showed wall thickening with homogeneous enhancement in the middle part of the stomach, and no lesions in the liver. The patient underwent laparoscopic distal gastrectomy with regional lymphadenectomy, and during the operation a small whitish nodule was observed on the lateral segment of the liver surface. The lesion was excised by partial resection of the liver for the purpose of both histological diagnosis and treatment. Pathological examination of the liver lesion revealed no structural or cellular atypia, no stromal invasion, and immunohistochemical positivity for CK7 and CK19, but negativity for p53. The final diagnosis was well-differentiated adenocarcinoma invading the gastric serosal layer without lymph node metastasis, and intrahepatic BDA measuring 0.4 × 0.3 cm. Following surgery, the patient remained symptom-free without evidence of recurrence for 5 months. To the best of our knowledge, this is the first case of BDA with gastric cancer. Because it is difficult to distinguish BDA from other liver tumors including metastatic cancer due to its characteristically small size and lack of specific morphological features on standard imaging, surgical resection should be considered as the most suitable approach for both accurate diagnosis and treatment.

Generation and characteristics of a novel "double-hit" high grade B-cell lymphoma cell line DH-My6 with MYC/IGH and BCL6/IGH gene arrangements and potential molecular targeted therapies

“Double-hit” lymphoma (DHL) is a high-grade B-cell lymphoma that harbors concurrent MYC and BCL2 or BCL6 rearrangements. Because cases of MYC/BCL6 DHL are uncommon, most reported conclusions have been based on cases of MYC/BCL2 DHL. Lack of experimental MYC/BCL6 DHL models continues to hinder the pathophysiologic and therapeutic investigations of this disorder. We herein describe a novel MYC/BCL6 DHL cell line, designated DH-My6, carrying both the MYC–IGH and BCL6–IGH fusion genes. Interruptions of MYC and BCL6 expressions using short interfering RNAs and chemical inhibitors led to significant attenuation of DH-My6 cell growth. Greater antitumor effects were found when the cells were treated with a combination of MYC and BCL6 inhibitors. Moreover, the PLK1 inhibitor volasertib and the HDAC inhibitor vorinostat synergized strongly when combined with the bromodomain inhibitor JQ1. DH-My6 is a new well-validated MYC/BCL6 DHL cell line that will provide a useful model for studies of the pathogenesis and therapeutics for the less common DHL tumor type. The rationale for approaches targeting both MYC and BCL6, and in combination with PLK1 or HDAC inhibitors for superior suppression of the aggressive MYC/BCL6 DHL warrants further in vivo testing in a preclinical model.

Merkel cell polyomavirus and Langerhans cell neoplasm

BACKGROUND

The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV.

METHODS

We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data.

RESULTS

We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH.

CONCLUSION

We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Killer cell immunoglobulin-like receptor 2DL4 is expressed in and suppresses the cell growth of Langerhans cell histiocytosis

Killer cell immunoglobulin-like receptor (KIR) 2DL4 (CD158d) is a receptor for human leukocyte antigen-G. The function of KIR2DL4 has been reported in human natural killer cell lymphoma and mastocytosis, but not in Langerhans cell histiocytosis (LCH). Herein, we examined the expression and function of KIR2DL4 in LCHs. In pathological specimens, 27 of 36 LCH cases (75.0%) were immunohistochemically positive for KIR2DL4. Its expression was independent of age, gender, location, multi- or single-system, and the status of BRAFV600E immunostaining. We also confirmed the expression of KIR2DL4 mRNA and protein in the human LCH-like cell lines ELD-1 and PRU-1. KIR2DL4 protein was distributed in the membrane and cytoplasm of ELD-1 cells, but only in the cytoplasm of PRU-1 cells. An agonistic antibody against KIR2DL4 reduced phosphorylation of extracellular signal-regulated kinases (ERKs) and suppressed the cell growth of ELD-1 cells in a Src homology region 2 domain-containing phosphatase-2 dependent manner, but it had no effect in PRU-1 cells. These results suggest that KIR2DL4-mediated ERK suppression is a possible therapeutic target for LCH cells.

Lymph node retrieval after dissolution of surrounding adipose tissue for pathological examination of colorectal cancer

Examination of >12 lymph nodes (LNs) is important for the diagnostic accuracy of nodal status following resection of colorectal cancer. In the present study, the efficacy of a fat dissolution technique for LN retrieval was evaluated using resected colon and rectum mesentery. First, the resected mesentery was searched for LNs by inspection and palpation immediately after surgery. Subsequently, fat dissolution liquid was applied to the remnant fat and the LN search was repeated. The primary endpoint was whether the second assessment would increase the number of evaluated LNs. Recruitment of 20 patients was planned. The study was conducted after institutional review board approval and written informed consent was obtained. Among 20 participants, 1 patient was excluded because LN dissection was not performed. The median number of LNs identified at the first and second assessments was 13 and 6, respectively, producing a significant increase in total LNs evaluated (13 vs. 20, respectively; P<0.01; paired t-test). One positive node was identified among the additionally identified LNs (0.9%, 1/107). The second assessment increased the number of LNs assessed to >12 in 4 patients, and although staging was not changed, the treatment was potentially altered in 2 stage II patients. The maximum diameter of the additionally obtained LNs was significantly smaller compared with those from the first assessment (4 vs. 7.7 mm, respectively; P<0.01; Wilcoxon signed-rank test). After the fat dissolution technique, the tumor cells were satisfactorily stained by carcinoembryonic antigen and cytokeratin-20. In conclusion, applying fat dissolution liquid to the remnant adipose tissue of the mesentery of the colon and rectum identified additional LNs. This method should be considered when insufficient LNs are identified after conventional LN retrieval.

Questiomycin A stimulates sorafenib-induced cell death via suppression of glucose-regulated protein 78

Hepatocellular carcinoma (HCC) is one of the most difficult cancers to treat owing to the lack of effective chemotherapeutic methods. Sorafenib, the first-line and only available treatment for HCC, extends patient overall survival by several months, with a response rate below 10%. Thus, the identification of an agent that enhances the anticancer effect of sorafenib is critical for the development of therapeutic options for HCC. Endoplasmic reticulum (ER) stress response is one of the methods of sorafenib-induced cell death. Here we report that questiomycin A suppresses expression of GRP78, a cell-protective ER chaperone protein. Analysis of the molecular mechanisms of questiomycin A revealed that this compound stimulated GRP78 protein degradation in an ER stress response-independent manner. Cotreatment with sorafenib and questiomycin A suppressed GRP78 protein expression, which is essential for the stimulation of sorafenib-induced cell death. Moreover, our in vivo study demonstrated that the coadministration of sorafenib and questiomycin A suppressed tumor formation in HCC-induced xenograft models. These results suggest that cotreatment with sorafenib and questiomycin A is a novel therapeutic strategy for HCC by enhancing sorafenib-dependent ER stress-induced cell death, and downregulation of GRP78 is a new target for the stimulation of the therapeutic effects of sorafenib in HCC.

Aberrant expression of AID and AID activators of NF-κB and PAX5 is irrelevant to EBV-associated gastric cancers, but is associated with carcinogenesis in certain EBV-non-associated gastric cancers

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is a distinct subtype of gastric cancer characterized by clinicopathological features including lymphoepithelioma-like histology. Aberrant expression of activation-induced cytidine deaminase (AID) as a genomic modulator was demonstrated through pathogen-related nuclear factor κB (NF-κB) signaling in Helicobacter pylori-associated gastric cancer. To elucidate whether or not AID expression is relevant to carcinogenesis in EBVaGC, immunohistochemical expression of AID and AID-regulatory factors between EBVaGC and EBV-non-associated gastric carcinoma (GC) were evaluated, each using 15 cases of GC with lymphoid stroma (GCLS) and other types of GC. Aberrant expression of AID, NF-κB and paired box 5 (PAX5) were significantly decreased in EBVaGC (0/11, 1/11 and 1/11) compared with in EBV-non-associated GC (7/19, 12/19 and 11/19) (P=0.025, 0.005 and 0.01, respectively); however, no significant difference in c-Myb proto-oncogene expression was identified. AID expression was also decreased in EBV-associated GCLS (0/10) compared with in EBV-non-associated GCLS (3/5). Unexpectedly, decreased expression of NF-κB and PAX5 was observed in GCLS (1/15 and 2/15) compared with in GC without LS (12/15 and 10/15) (P<0.001 and P=0.003, respectively). Decreased AID expression observed in EBVaGC is consistent with the reported molecular characterization of hypermethylation and rare somatic gene mutation in EBVaGC. Only PAX5 was identified to be significantly associated with venous invasion (P=0.022). The results of the present study suggest that pathogen-induced AID expression may be irrelevant to carcinogenesis of EBVaGC, whereas it contributes to carcinogenesis in certain types of EBV-non-associated GC.

Epstein-Barr Virus Lytic Reactivation Activates B Cells Polyclonally and Induces Activation-Induced Cytidine Deaminase Expression: A Mechanism Underlying Autoimmunity and Its Contribution to Graves' Disease

Graves' disease is an autoimmune disease that results in and is the most common cause of hyperthyroidism, and the reactivation of persisting Epstein–Barr virus (EBV) in B lymphocytes induces the differentiation of host B cells into plasma cells. We previously reported that some EBV-infected B cells had thyrotropin receptor antibodies (TRAbs) as surface immunoglobulins (Igs), and EBV reactivation induced these TRAb+EBV+ cells to produce TRAbs. EBV reactivation induces Ig production from host B cells. The purpose of the present study was to examine total Ig productions from B cell culture fluids and to detect activation-induced cytidine deaminase (AID), nuclear factor kappa B (NF-κB), and EBV latent membrane protein (LMP) 1 in culture B cells during EBV reactivation induction and then we discussed the mechanisms of EBV reactivation-induced Ig production in relation to autoimmunity. We showed that the EBV reactivation induces the production of every isotype of Ig and suggested that the Ig production was catalyzed by AID through LMP1 and NF-κB. The results that the amount of IgM was significantly larger compared with IgG suggested the polyclonal B cell activation due to LMP1. We proposed the pathway of EBV reactivation induced Ig production; B cells newly infected with EBV are activated by polyclonal B cell activation and produce Igs through plasma cell differentiation induced by EBV reactivation. LMP1-induced AID enabled B cells to undergo class-switch recombination to produce every isotype of Ig. According to this mechanism, EBV rescues autoreactive B cells to produce autoantibodies, which contribute to the development and exacerbation of autoimmune diseases.

Acute undifferentiated leukemia (stem cell acute leukemia) showing differentiation to Langerhans cell-like cells in lymph nodes

A 75-year-old woman was referred to our hospital with suspected leukemia. Complete blood count demonstrated WBC 3,810/µl with 26% blasts, Hb of 11.7 g/dl and Plt of 18.0×10⁴/µl. Bone marrow aspiration revealed blasts (86.3%) with expressions of CD34, CD7, TdT, CD33, and CD117. MPO was negative. Chromosomal analysis of the bone marrow showed isolated trisomy 10 in all leukemic cells (20/20). Swelling of superficial lymph nodes was also observed. Cervical lymph node biopsy revealed leukemic blasts which had the same phenotype as those in the bone marrow except that proliferation of Langerhans cell-like cells (LCs) was observed in the paracortex. LCs had pale cytoplasm and grooved nuclei, and were positive for both CD1a and S100 protein. Trisomy 10 was detected in both the leukemic blasts and the LCs by fluorescence in situ hybridization. This rare case strongly suggests leukemic cells to differentiate into LCs.

Thyrotropin Receptor Antibody (TRAb)-IgM Levels Are Markedly Higher Than TRAb-IgG Levels in Graves' Disease Patients and Controls, and TRAb-IgM Production Is Related to Epstein-Barr Virus Reactivation

Graves' disease is an autoimmune thyroid disorder that mainly presents as hyperthyroidism and is caused by thyrotropin receptor antibodies (TRAbs) that stimulate thyroid-stimulating hormone receptors. We previously reported that Graves' disease patients and healthy controls both had Epstein–Barr virus (EBV)-infected TRAb-positive B cells and the EBV-reactivated induction of these B cells in cultures may induce the production of TRAbs. In the present study, we quantified serum TRAb-IgG and TRAb-IgM levels in 34 Graves' disease patients and 15 controls using ELISA to elucidate the mechanisms underlying EBV-related antibody production. As expected, TRAb-IgG and TRAb-IgM levels were higher in Graves' disease patients than in controls; however, TRAb-IgM levels were significantly higher than those of TRAb-IgG levels, whereas total IgM levels were lower than total IgG levels. On the other hand, the enhanced production of TRAb-IgM was frequently observed in patients with EBV reactivation. These results are consistent with the fact that the percentage of autoreactive IgM B cells are higher than that of autoreactive IgG B cells, and support the EBV-related polyclonal B cell activation. It is necessary to clarify the biological characteristics of TRAb-IgM and the relationship between TRAb isotypes and the biology of Graves' disease.