Keiji Kodama

Predictive markers for late cervical metastasis in stage I and II invasive squamous cell carcinoma of the oral tongue

Purpose: Patients with oral tongue carcinoma treated by intraoral excision only should be followed up carefully for cervical lymph node metastasis and salvaged immediately if found, because some patients have a more aggressive clinical course. The purpose of this study was to find useful markers for predicting late cervical metastasis in patients with stage I and II invasive squamous cell carcinoma of the oral tongue. Experimental Design: We investigated clinicopathologic factors and immunohistochemical biomarkers predicting late cervical metastasis in surgical specimens from 56 patients with T1–2N0M0 invasive squamous cell carcinoma of the oral tongue who did not undergo elective neck dissection. Histopathologic factors including tumor thickness, mode of invasion, Broders grade, total score of three different malignancy grading systems, eight other clinicopathologic parameters, and immunohistochemical expression of p53, cyclin D1, Ki-67, epidermal growth factor receptor, microvessel density, cyclooxygenase-2, MUC1, laminin-5 γ2, E-cadherin, and β-catenin were examined. All of the clinicopathologic factors and immunohistochemical expression of biomarkers were compared in terms of survival. Results: In the univariate analysis, tumor thickness (P = 0.009), Broders grade (P = 0.017), nest shape (P = 0.005), mode of invasion (P < 0.001), Anneroth score (P = 0.029), Bryne score (P < 0.001), and E-cadherin expression (P = 0.003) were correlated with late cervical metastasis. Multivariate analysis on late cervical metastasis revealed that tumor thickness >4 mm, mode of invasion grade 3 or 4, and E-cadherin expression were independent factors. Late cervical metastasis was the only prognostic factor for overall survival (P = 0.002). Conclusions: Our results indicate that patients with stage I and II invasive squamous cell carcinoma of the oral tongue with tumor thickness >4 mm, mode of invasion grade 3 or 4, and low expression of E-cadherin should be considered a high-risk group for late cervical metastasis when a wait-and-see policy for the neck is adopted.

Matrix Metalloproteinase-7 Facilitates Insulin-Like Growth Factor Bioavailability through Its Proteinase Activity on Insulin-Like Growth Factor Binding Protein 3

Matrix metalloproteinase-7 (MMP-7) secreted by cancer cells has been implicated classically in the basement membrane destruction associated with tumor cell invasion and metastasis. Recent epidemiologic studies have established a correlation between high levels of circulating insulin-like growth factor (IGF) and low levels of IGF binding protein 3 (IGFBP-3), and relative risk of developing colon, breast, prostate, and lung cancer, which are known to produce MMP-7. In this study, IGFBP-3 was assessed as a candidate for the physiologic substrate of MMP-7. MMP-7 proteolysis generated four major fragments (26 kDa, 17 kDa, 15.5 kDa, and 15.5 kDa), and two cleavage sites were identified: one at the site of hydrolysis of the K144-I145 peptide bond and one at the R95-L96 peptide bond. The former site is different from the previously reported site of cleavage of IGFBP-3 by other proteases. Addition of IGFBP-3 inhibited IGF-I-mediated IGF type 1 receptor (IGF-IR) phosphorylation and activation of the downstream molecule Akt in BALB/c 3T3 fibroblasts overexpressing human IGF-IR (3T3-IGF-IR) and in two human colon cancer cell lines (COLO201 and HT29). Coincubation of the IGF-I/IGFBP-3 complex with MMP-7 restored IGF-I-mediated IGF-IR phosphorylation and activation of Akt in these cell lines. The IGF-I signal recovered by MMP-7 protected against apoptosis induced by anoikis in 3T3-IGF-IR cells. These results indicate that MMP-7 proteolysis of IGFBP-3 plays a crucial role in regulating IGF-I bioavailability, thereby promoting cell survival. This mechanism may contribute to the tumorigenesis of MMP-7-producing IGF-IR-expressing tumors in the primary site and to organ-specific metastasis in a paracrine manner.

Growth Inhibition of Human Prostate Cancer Cells in Human Adult Bone Implanted into Nonobese Diabetic/Severe Combined Immunodeficient Mice by a Ligand-Specific Antibody to Human Insulin-Like Growth Factors

Advanced prostate cancer frequently involves the bone that has the largest content of insulin-like growth factors (IGFs). However, the role of bone-derived IGFs in bone metastasis of prostate cancer has not been studied extensively because of the lack of a reliable animal model. Therefore, we investigated whether a novel antibody directed against human IGF-I and IGF-II (KM1468) could inhibit the development of new bone tumors and the progression of established bone tumors in nonobese diabetic/severe combined immunodeficient mice implanted with human adult bone. We first confirmed that KM1468 bound specifically to human IGF-I, human IGF-II, and mouse IGF-II but not to insulin. It also blocked autophosphorylation of the type I IGF receptor induced by the binding of IGFs in human-type I IGF receptor-overexpressing BALB/c 3T3 cells, and it inhibited the IGF-stimulated growth of MDA PCa 2b cells in vitro. Then mice were injected intraperitoneally with KM1468 once weekly for 4 weeks either immediately or 4 weeks after inoculation of MDA PCa 2b cells. KM1468 markedly and dose-dependently suppressed the development of new bone tumors and the progression of established tumor foci, as determined by histomorphometry, and it also decreased serum prostate-specific antigen levels, compared with the control. This is the first report of an IGF ligand-specific inhibitory antibody that suppresses the growth of human prostate cancer cells in human adult bone. These results indicate that the IGF signaling axis is a potential target for prevention and treatment of bone metastases arising from prostate cancer.

Blockade of Paracrine Supply of Insulin-Like Growth Factors Using Neutralizing Antibodies Suppresses the Liver Metastasis of Human Colorectal Cancers

Environmental stimuli, such as organ-specific growth factors, can influence the metastatic potential of a tumor. The liver is the main source of insulin-like growth factors (IGFs). The importance of IGF signal in hepatic metastasis has been clarified mainly by IGF-I receptor targeting strategies. This study aims to confirm these precedent reports by novel tool, neutralizing antibodies against IGFs and to show that IGFs are promising therapeutic targets for hepatic metastasis in vivo. Hepatic metastasis was induced by intrasplenic injection of human colorectal cancer cell line, HT29. The antimetastatic effects of three antibodies (anti-mouse IGF-I, anti-mouse IGF-II, and anti-human/mouse IGF-II designated KM1468) were tested singly or in combination in the early phase of metastasis. The dose escalation effect of KM1468 and its survival benefit were examined in the early and late phases of metastasis. The mechanism of IGF neutralization was investigated with immunohistochemistry. Dual neutralization of paracrine IGF-I and IGF-II showed modest additive antimetastatic effects than single neutralization of IGF-I or IGF-II. In any phase of metastasis, neutralization led to significant tumor growth inhibition and longer survival. Dose escalation of KM1468 influenced survival only in the late phase of metastasis. Apoptosis increased significantly in the antibody-treated group compared with the control group (P = 0.0025) In conclusion, IGFs are promising therapeutic targets for hepatic metastases of colorectal cancers. However, the IGF dependency is probably variable in the metastatic process.

Effect of differences in cancer cells and tumor growth sites on recruiting bone marrow-derived endothelial cells and myofibroblasts in cancer-induced stroma

Cancer‐stromal interaction is well known to play important roles during cancer progression. Recently we have demonstrated that bone marrow‐derived vascular endothelial cells (BMD‐VE) and myofibroblasts (BMD‐MF) are recruited into the human pancreatic cancer cell line Capan‐1 induced stroma. To assess the effect of the difference in cancer cell types on the recruitment of BMD‐VE and BMD‐MF, 10 kinds of human cancer cell line were implanted into the subctaneous tissue of the immunodeficient mice transplanted with bone marrow of double‐mutant mice (RAG‐1−/− β‐gal Tg or RAG‐1−/− GFP Tg). The recruitment frequency of BMD‐VE (%BMD‐VE) and BMD‐MF (%BMD‐MF), and tumor‐associated parameters [tumor volume (TV), microvessel density (MVD) and stromal proportion (%St)] were measured. The correlation among them was analyzed. Although %BMD‐VE and %BMD‐MF varied (from 0 to 21.6%, 0 to 29.6%, respectively), depending on the cancer cell line, both parameters were significantly correlated with %St (p < 0.005). Furthermore %BMD‐VE and %BMD‐MF also significantly correlated (p < 0.005). In order to assess the effect of tumor growth sites on the recruitment of the cells of interest, a human pancreatic cancer cell line, Capan‐1, was transplanted into 5 different sites: subcutaneous tissue, peritoneum, liver, spleen and lung. Tumors in the subcutaneous tissue and peritoneum induced desmoplastic stroma (%St = 22.7%, 19.5%, respectively) and contained BMD‐VE (%BMD‐VE = 21.6%, 16.5% respectively) and BMD‐MF (%BMD‐MF = 29.6%, 24.5%, respectively), but weak stromal induction without recruitment of BMD‐VE or ‐MF was observed in the tumors at of the liver, spleen and lung (%St = 9.7%, 9.1%, 5.4%, respectively). cDNA microarray analysis identified the 29 genes that expression was especially up‐ or down‐regulated in the cell line that induced an abundant stromal reaction. However they did not encoded the molecules that were directly involved in stromal cell recruitment (chemokines), differentiation (cytokines) or proliferation (growth factors). These results indicate that the recruitment of BMD‐VE and ‐MF is required for stromal formation during cancer progression and that the cancer microenvironment is important in stromal reaction and the recruitment of BMD‐VE and ‐MF.

Frequent overexpression of the c-kit protein in large cell neuroendocrine carcinoma of the lung

Overexpression of receptor-type tyrosine kinases in various cancers is associated with an aggressive tumor phenotype and poor outcome, but their expression had never been evaluated in large cell neuroendocrine carcinoma (LCNEC) of the lung. In the present study, we investigated the expression of three receptor tyrosine kinases, epidermal growth factor receptor (EGFR), c-erbB-2, and c-kit protein, by comparing surgically resected 40 LCNECs with other neuroendocrine (NE) lung tumors: 9 typical carcinoids (TCs), 5 atypical carcinoids (ACs), and 13 small cell lung carcinomas (SCLCs). None of the NE lung tumors showed expression of EFGR or c-erbB-2, but c-kit was overexpressed in 55% of the LCNEC tumor cells and 46% of the SCLC tumor cells. None of the clinicopathologic factors in either the LCNEC or SCLC patients correlated with c-kit overexpression. The finding that c-kit expression in LCNEC is similar to its expression in SCLC suggests that inhibition of c-kit may be effective as a therapy targeting LCNEC as well as SCLC.

Laminin 5 expression protects against anoikis at aerogenous spread and lepidic growth of human lung adenocarcinoma.

Adenocarcinoma of the lung is characterized by frequent aerogenous spread (AE) and advancement along the alveolar wall (BAC growth). To elucidate the mechanism of AE metastasis and BAC growth in human lung adenocarcinoma, we established an in vivo orthotopic animal model and an in vitro culture. Investigation of expression levels of integrins, laminins and Type IV collagens, which are the major regulating molecules for cell attachment and anoikis was carried out and a clear correlation between the expression level of laminin 5 (LN5) and the BAC growth was observed using an orthotopic animal model. Introduction of LN5 cDNA to A549 cells increased anoikis resistance in an expression dependent manner. Cells with LN5 overexpression resisted with anoikis after treatment with PI3K‐Akt and ERK inhibitors. The amount of phosphorylated focal adhesion kinase (FAK) was also higher in LN5 overexpressing cells. Major tyrosine residues of the EGF receptor at 1068, 1086 and 1173, except at 1148, remained phosphorylated only in the LN5 overexpressing cells even without EGF stimulation, that indicates the ligand independent activation of EGF receptor. BAC growth ratio and AE was confirmed to be significantly correlated with LN5 expression in surgically resected human lung adenocarcinomas by immunohistochemistry. Our results indicate that the activation of the EGF receptor by overexpressing LN5‐integrin‐FAK signaling pathway may play a crucial role in BAC growth and AE metastasis in human lung adenocarcinoma.

Low-grade B-cell lymphoma of mucosa-associated lymphoid tissue in the lung: a report of a case with pleural dissemination

A 79-year-old man with an abnormal shadow on a chest radiograph was referred to our hospital for further examination. Open lung biopsy revealed numerous nodules on visceral pleura and the tumor, obtained by wedge resection of the left upper lobe of the lung, consisted of centrocyte-like cells and lymphoplasmacytoid cells, expressing CD20 and CD79a. These cells invaded bronchiolar epithelium to form lymphoepithelial lesions. The pleural-based nodules were similarly composed of the same cells as those in the left upper lobe tumor. To our knowledge, pleural dissemination of low grade B-cell lymphoma of mucosa-associated lymphoid tissue has not been reported previously.

Topographical distribution of allelic loss in individual lung adenocarcinomas with lymph node metastases

Adenocarcinomas of the lung are characterized by morphological heterogeneity, and since carcinogenesis has been suggested to be a multistep process involving sequential accumulation of multiple genetic alterations, the morphological heterogeneity may represent a cross-sectional view of genetic alterations within individual tumors. Therefore, to elucidate whether, and which, genetic alterations accumulated in relation to morphological cancer progression, we examined 56 microdissected sites for topographical distribution of loss of heterozygosity (LOH) in 12 adenocarcinomas of the lung with bronchioloalveolar (BA) and invasive components in their primary tumors and metastases to lymph nodes. The morphological changes from noninvasive BA lesions to invasive and metastatic components were characterized by a significant rise in the prevalence of allelic losses (P<0.05). Individually, eight cases (67%) showed accumulation of genetic alterations from BA lesions to metastases. LOHs in multiple foci in one case were compared to determine whether they were shared at all tumor sites as an early event or localized in metastases as an additional event. LOHs at 5q and 17p may be crucial steps in the early phase of development to metastasis, while 18q loss may be an additional step. These findings suggested that the cancer cells in some pulmonary adenocarcinomas evolved from the BA lesions to the invasive and metastatic lesions.

Treatable Subsets in Cancer of Unknown Primary Origin

The purpose of this study was to investigate the treatable subsets in cancer of unknown primary origin (CUP). Fifty patients (27 males and 23 females; median age, 53 years) with CUP diagnosed between April 1992 and June 1999 were analyzed retrospectively. Of the 50 patients, 39 received chemotherapy: platinum‐based in 31, non‐platinum‐based in 4, and clinical trials of new agents in 4. Of the 39 patients, 13 (33.3%; 95% confidence interval: 19.1–50.2%) showed objective responses, with 4 complete responders. Patients with poorly differentiated carcinomas in whom p‐subunit of human chorionic gonadotropin (β‐HCG) was elevated more than 10 mlU/ml and female patients with peritoneal adenocarcinomatosis achieved high response rates (83.3% and 80%, respectively) with platinum‐based chemotherapy, as compared with only a 15.3% response rate in the remaining patients. Platinum‐based chemotherapy provided promising results in patients with poorly differentiated carcinomas and in female patients with peritoneal adenocarcinomatosis. Significantly elevated serum levels of β‐HCG in patients with poorly differentiated carcinoma might predict a better response to platinum‐based chemotherapy. However, the investigation of novel chemotherapeutic approaches is warranted for other groups of patients with CUP.