Combination of naproxen and a chemically-stable eicosapentaenoic acid analog provide additive tumor protection in Pirc rats.

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. Patients with the genetic disorder Familial Adenomatous Polyposis (FAP) develop hundreds to thousands of polyps that unless removed by prophylactic colectomy will progress to CRC at an early age. Nonsteroidal anti-inflammatory drugs (NSAIDs) and the ω-3 polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (EPA), have been evaluated for their chemopreventive potential in delaying CRC onset in high-risk patients. In our study, we determined whether the NSAID, naproxen, alone or in combination with a chemically-stable EPA analog (TP-252), affects tumor formation in the ApcPirc rat model. When compared to control diet, animals fed naproxen or HD TP-252 had 66% and 82% fewer tumors, respectively. However, animals fed a combination of naproxen and HD TP-252, exhibited a 95% reduction in tumor formation and a 98% reduction in tumor volume, respectively. To elucidate potential mechanisms of tumor protection, a comprehensive, targeted lipidomic analysis was performed on colonic mucosa to determine changes in eicosanoid metabolism. Animals receiving TP-252 alone or in combination with naproxen had significantly reduced mucosal levels of proinflammatory ω-6 eicosanoids (PGE2 , 5-HETE and 14,15-DiHETrE), along with a simultaneous increase in anti-inflammatory EPA-derived ω-3 eicosanoids. A comprehensive lipidomic analysis also uncovered several potential pharmacodynamic (PD) lipid biomarkers, including resolvin E2, 9-HEPE, 12-HEPE and 18-HEPE, that were significantly correlated with tumor protection. Further studies with this drug combination should be focused on dose optimization and the role of EPA-derived lipid mediators in CRC initiation and progression.

The pathology according to p53 pathway.

Background Observations play a pivotal role in the progress of science, including in pathology. The cause of a disease such as cancer is analyzed by breaking it down into smaller organs, tissues, cells, and molecules. The current standard cancer diagnostic procedure, microscopic observation, relies on preserved morphological characteristics. In contrast, molecular analyses explore oncogenic pathway activation that leads to genetic mutations and aberrant protein expression. Such molecular analyses could potentially identify therapeutic targets and has gained considerable attention in clinical oncology. Summary This review summarizes the cardinal biomarkers of the p53 pathway, p53, p16, and mouse double minute 2 (MDM2), in the context of traditional surgical pathology and emerging genomic oncology. The p53 pathway, which is dysregulated in more than a half of all cancers, can be applied in several diagnostic settings. A four-classification model of immunophenotype for p53 pathway gene status, tumor types with a high frequency of abnormalities for each p53 pathway gene, and a minimal p53 pathway immunohistochemical panel is also described. Key messages Immunohistochemistry of oncogenic signals should be interpreted according to molecular findings based on genomic oncology, in addition to the microscopic findings of diagnostic pathology.

A comparative analysis of MRI findings in endometrial cancer: differentiation between endometrioid adenocarcinoma, serous carcinoma, and clear cell carcinoma.

OBJECTIVE: To assess the magnetic resonance imaging (MRI) findings of endometrial cancers and to reveal the differences between endometrioid carcinoma (EC), serous carcinoma (SC), and clear cell carcinoma (CCC). METHODS: In this study, 274 consecutive patients with histopathologically confirmed endometrial cancer (231 ECs, 25 SCs, and 18 CCCs) who underwent MRI before hysterectomy were enrolled. MRI images were retrospectively reviewed and compared between the three pathologies. RESULTS: The maximum diameters (55.6 ± 34.7 vs. 39.3 ± 21.6 vs. 39.4 ± 26.8 mm) (p < 0.05) and apparent diffusion coefficient (ADC) values (1.11 ± 0.21 vs. 0.84 ± 0.17 vs. 0.86 ± 0.16 × 10-3 mm2/s) (p < 0.01) were significantly greater in CCCs than in ECs and SCs, respectively. Infiltrative growth pattern (33% vs. 6%) (p < 0.01) was more frequent in CCCs than in ECs. Peritoneal dissemination (16% vs. 0%) (p < 0.01) and heterogeneous signal on diffusion-weighted (61% vs. 32%) (p < 0.05) images were more frequent in SCs than in ECs, respectively. Abnormal ascites (12% vs. 11% vs. 0%) and heterogeneous signal on T1-weighted (28% vs. 50% vs. 9%), T2-weighted (64% vs. 72% vs. 36%), and fat-suppressed gadolinium-enhanced T1-weighted (80% vs. 90% vs. 46%) images were more frequent in SCs and CCCs than in ECs, respectively (p < 0.05). CONCLUSIONS: SCs frequently exhibited a heterogeneous signal with peritoneal dissemination and abnormal ascites. Alternatively, CCCs tended to have a larger tumor size and higher ADC values with an infiltrative growth pattern, heterogeneous signal, and abnormal ascites. KEY POINTS: • SCs tend to have a heterogeneous signal intensity with peritoneal dissemination and abnormal ascites compared to ECs. • CCCs tend to have a heterogeneous signal intensity with an infiltrative growth pattern and abnormal ascites compared to ECs. • CCCs have a larger tumor size and higher ADC values compared to ECs and SCs.

Macroscopic visible core length can predict the histological sample quantity in endoscopic ultrasound-guided tissue acquisition: Multicenter prospective study.

OBJECTIVES: Measurement of the macroscopic visible core (MVC) length during macroscopic on-site quality evaluation (MOSE) may allow estimation of sample adequacy for next-generation sequencing (NGS), and prediction of correct diagnosis in endoscopic ultrasound-guided tissue acquisition (EUS-TA) of pancreatic masses. METHODS: This multicenter prospective study included consecutive patients who underwent EUS-TA for pancreatic masses using a 22-G Franseen needle. MVC length and pathological samples obtained from two needle passes were analyzed on a per-pass basis. Outcome measures included respective correlations of MVC length with histological sample quantity and diagnostic yields. RESULTS: The analysis included 204 passes from 102 EUS-TAs. MVC length correlated positively with histological sample quantity (P < 0.01). On the receiver operating characteristic curve for MVC length, the cut-off value and area under the curve for obtaining a candidate sample for NGS were 30 mm and 0.74 (95% confidence interval [CI] 0.65-0.83), respectively. On multivariate analysis, MVC length ≥30 mm was a significant factor affecting suitability for NGS (odds ratio 6.19; 95% CI 2.72-14.10). Histologic diagnostic yield correlated positively with MVC length (P = 0.01); however, there was no positive correlation between MVC length and overall (histology plus cytology) diagnostic yield. CONCLUSIONS: Measuring MVC length to predict histological sample quantity on MOSE may be of clinical significance during EUS-TA using a 22-G Franseen needle. It may be an effective method, particularly while submitting samples for NGS. REGISTRATION: University Hospital Medical Information Network Trials Registry (UMIN000036528).

Specific Deletion of p16INK4a with Retention of p19ARF Enhances the Development of Invasive Oral Squamous Cell Carcinoma.

The cyclin-dependent kinase inhibitor 2A (CDKN2A)/alternate reading frame (ARF) locus consists of two overlapping tumor suppressor genes, p16INK4a and p14ARF (p19ARF in mice), encoding two unrelated proteins in alternative reading frames. Previous reports suggest that p16INK4a and p14ARF alterations independently exhibit differential roles, and p16INK4a is more closely associated with a poor prognosis in oral cancer. However, the role of p16INK4a-specific loss in oral squamous cell carcinogenesis remains unclear. The authors assessed chemical carcinogen 4-nitroquinoline 1-oxide (4NQO)-induced multistep oral squamous cell carcinogenesis in mice carrying p16INK4a-specific loss with retention of the p19ARF gene (p16INK4a-/-). 4NQO-treated p16-/- mice exhibited a higher incidence and multiplicity of oral squamous cell carcinoma (OSCC) development relative to 4NQO-treated wild-type mice. 4NQO-treated p16INK4a-/- OSCC cells exhibited higher proliferation and up-regulation of Arf, transcription factor E2f1, tumor protein p63 (tp63), and oncogenic ΔNp63, an isoform p63, compared with observations in 4NQO-treated wild-type OSCC cells. Furthermore, the overexpression of oncogenic ΔNp63 was associated with human OSCC. In conclusion, these results in mice indicate the biological significance of p16INK4a-specific loss with retention of p19ARF in oral squamous cell carcinogenesis, and ΔNp63 may be a potential target for OSCC.

Magnetic resonance imaging findings of extrauterine high-grade serous carcinoma based on new pathologic criteria for primary site assignment.

BACKGROUND: There has been no study that has reported magnetic resonance imaging (MRI) findings of extrauterine high-grade serous carcinomas (HGSCs) that have been histologically determined by the new criteria. PURPOSE: To assess MRI findings of extrauterine HGSCs based on new pathologic criteria. MATERIAL AND METHODS: Fifty patients with histopathologically proven extrauterine HGSCs, who underwent pretreatment gadolinium-enhanced MRI, were included in this study. After surgery, the primary sites were histopathologically determined based on new criteria for primary site assignment in extrauterine HGSCs as follows: fallopian tube (n = 34); ovary (n = 9); primary peritoneal HGSC (n = 1); and tubo-ovarian (n = 6). We retrospectively reviewed MR images and compared the MR findings between tubal and ovarian primaries. RESULTS: MRI patterns with tubal primaries were classified as ovarian cancer (62%), peritoneal cancer (35%), and fallopian tube cancer (3%). MRI patterns with ovarian primaries were classified as ovarian cancer (78%) and peritoneal cancer (22%). The frequency of the involvement of the fallopian tube, ovary, peritoneum, uterus, and lymph node was not significantly different between the two pathologies. There was no significant difference in the abnormal amount of ascites, hemorrhagic ascites, or characteristics of the ovarian lesions between the two pathologies. CONCLUSION: On MR images, tubal primaries almost always exhibited ovarian or peritoneal cancer pattern, but rarely exhibited fallopian tube cancer pattern. MR findings could not accurately differentiate between tubal and ovarian primaries; therefore, histopathologic investigation is essential for determination of the primary site of extrauterine HGSCs.

[Paraurethral Leiomyoma in a Female Patient who Had Clinical Symptoms with Increase of Tumor Volume: A Case Report].

A 34-year-old woman underwent total hysterectomy for management of uterine leiomyoma. At the same time, a paraurethral tumor (2 cm in size) was diagnosed based on magnetic resonance imaging (MRI). However, the patient was not treated for the tumor considering its small size. Eight years later, the patient was referred to our institution with a chief complaint of urethral bleeding. Computed tomography revealed a paraurethral mass at the same location, which was 13 cm in size. A percutaneous needle biopsy was performed and the tumor was diagnosed as leiomyoma. Tumor extirpation was performed and immunohistochemical analysis of the specimen demonstrated positive estrogen and progesterone receptors. Recurrence was not observed on MRI taken 6 months after the surgery. Paraurethral leiomyoma is rare, but relatively common in young women.

[Renal Cell Carcinoma in the Left Pelvic Kidney : A Case Report].

We report the case of a 61-year-old man who was incidentally diagnosed with a left pelvic ectopic kidney with renal tumor. Computed tomography showed a hypervascular tumor at the posterior surface of the ectopic kidney with five arterial and two venous supply vessels. On preoperative examination, this patient had respiratory dysfunction. For these reasons, an open radical nephrectomy was performed. Histological examination revealed a clear cell renal cell carcinoma, pT1aN0M0, G1, and a Fuhrman nuclear grading system grade of G2. No evidence of disease was observed 15 months after surgery.

A Comprehensive Review of Ovarian Serous Carcinoma.

Although ovarian serous carcinoma is a well-studied human gynecologic malignancy, this high-grade tumor remains fatal. The main purpose of this review is to summarize the accumulated evidence on serous malignant tumors and to clarify the unresolved issues. We discuss the 8 dichotomies of serous carcinoma: high grade versus low grade, ovarian versus extraovarian primary, extrauterine versus uterine primary, sporadic versus hereditary, orthodox versus alternative histology, p53 overexpression versus complete absence of immunophenotype, TP53-mutated versus intact precursor, and therapy responsive versus refractory. In addition, we summarize the molecular classification of high-grade serous carcinoma. This review would lead readers to rapid and parallel developments in understanding high-grade serous carcinoma.

Heterogeneity of Colon Cancer Stem Cells.

Colorectal cancer (CRC) remains the fourth leading cause of cancer death worldwide. Cancer stem cells (CSCs) have attracted a great deal of interest because of their potential clinical implications in a range of cancers, including CRC. CSCs were initially considered to be cell populations with well-defined phenotypic and molecular characteristics. However, accumulating evidence suggests that CSCs represent a phenotypically and functionally heterogeneous population. Recent studies also demonstrate colorectal CSCs to be dynamic rather than static populations that are continuously altered by various extrinsic factors in addition to intrinsic cellular factors such as genetic and epigenetic alterations. Thus, CSCs do not represent a fixed target population any longer, and their heterogeneous and dynamic nature present a serious problem in establishing specific therapeutic strategies. This chapter summarizes past and current literature related to CSC population heterogeneity and dynamics in CRC tissues, including evidence of the presence of distinct CSC subpopulations and signaling pathways and intra- and extra-tumoral factors involved in the regulation of CSCs in cancer tissues.

A 19-Gauge Histology Needle Versus a 19-Gauge Standard Needle in Endoscopic Ultrasound-Guided Fine-Needle Aspiration for Solid Lesions: A Multicenter Randomized Comparison Study (GREATER Study).

BACKGROUND: The necessity of histological analysis is increasing. A 19-gauge histology needle (PC19) in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has recently been developed and has shown high yields of tissue acquisition and histological diagnosis. AIMS: To compare the histological diagnostic yield in single-pass EUS-FNA for solid lesions using PC19 and a standard 19-gauge needle (EC19). PATIENTS AND METHODS: Consecutive patients with solid lesions were enrolled and underwent one pass with each of PC19 and EC19 for EUS-FNA with the randomized order of the needles. The primary endpoint was the histological diagnostic accuracy. The secondary endpoints were the feasibility, yield of histological core, cytological and overall diagnostic accuracies, and adverse events. Subgroup analysis was performed for the optimal situation with PC19. RESULTS: Of the 115 patients, 110 underwent EUS-FNA and five were excluded. EUS-FNA was performed from the esophagus in four, stomach in 80, or duodenum in 26. The final diagnosis was malignancy in 100 and benign in 10. The feasibility was 98.2 and 97.3% with PC19 and EC19, respectively (p = 1.00). The rate of presence of a histological core and the histological, cytological, and overall diagnostic accuracies for PC19 versus EC19 were 84.6 versus 80.9% (p = 0.593), 83.6 versus 73.6% (p = 0.099), 63.6 versus 56.4% (p = 0.335), and 90.0 versus 79.1% (p = 0.039), respectively. PC19 was favored in the trans-esophageal/gastric approaches to obtain a histological diagnosis (p = 0.013). Adverse events were observed in four patients. CONCLUSION: Single-pass EUS-FNA with PC19 was feasible and showed significantly higher overall diagnostic accuracy and an increased tendency towards histological diagnostic accuracy, especially with trans-esophageal/gastric FNA.

Multifaceted Interpretation of Colon Cancer Stem Cells.

Colon cancer is one of the leading causes of cancer-related deaths worldwide, despite recent advances in clinical oncology. Accumulating evidence sheds light on the existence of cancer stem cells and their role in conferring therapeutic resistance. Cancer stem cells are a minor fraction of cancer cells, which enable tumor heterogeneity and initiate tumor formation. In addition, these cells are resistant to various cytotoxic factors. Therefore, elimination of cancer stem cells is difficult but essential to cure the malignant foci completely. Herein, we review the recent evidence for intestinal stem cells and colon cancer stem cells, methods to detect the tumor-initiating cells, and clinical significance of cancer stem cell markers. We also describe the emerging problems of cancer stem cell theory, including bidirectional conversion and intertumoral heterogeneity of stem cell phenotype.

Reducing DNA methylation suppresses colon carcinogenesis by inducing tumor cell differentiation.

The forced reduction of global DNA methylation suppresses tumor development in several cancer models in vivo. Nevertheless, the mechanisms underlying these suppressive effects remain unclear. In this report, we describe our findings showing that a genome-wide reduction in the DNA methylation levels induces cellular differentiation in association with decreased cell proliferation in Apc (Min/+) mouse colon tumor cells in vivo. Colon tumor-specific DNA methylation at Cdx1 is reduced in the DNA-hypomethylated tumors accompanied by Cdx1 derepression and an increased expression of intestinal differentiation-related genes. Furthermore, a histological analysis revealed that Cdx1 derepression in the DNA-hypomethylated tumors is correlated with the differentiation of colon tumor cells. Similarly, the treatment of human colon cancer cell lines with a hypomethylating agent induces differentiation-related genes, including CDX1. We herein propose that DNA demethylation exerts a tumor suppressive effect in the colon by inducing tumor cell differentiation.

Inhibition of indoleamine 2,3-dioxygenase 1 expression alters immune response in colon tumor microenvironment in mice.

Indoleamine 2,3-dioxygenase (IDO), an enzyme that degrades the essential amino acid l-tryptophan along the kynurenine pathway, exerts immunomodulatory effects in a number of diseases. IDO expression is increased in tumor tissue and in draining lymph nodes; this increase is thought to play a role in tumor evasion by suppressing the immune response. A competitive inhibitor of IDO is currently being tested in clinical trials for the treatment of relapsed or refractory solid tumors, but the efficacy of IDO inhibition in colorectal tumors remains to be fully elucidated. In this study, we investigated the effect of IDO deficiency on colon tumorigenesis in mice by genetic deletion and pharmacological inhibition. Ido1-deficient((-/-)) mice were crossed with Apc(Min/+) mice or were administered azoxymethane with or without dextran sodium sulfate. Ido1 deficiency did not lead to significant differences in the size and number of colon tumors. Similarly, the pharmacological inhibition of IDO using 1-methyltryptophan (1-mT) also resulted in no significant differences in tumor size and number in Apc(Min/+) mice. However, Ido1 deficiency altered the immune response in the tumor microenvironment, showing a significant increase in mRNA expression of pro-inflammatory cytokines and a significant decrease in the number of Foxp3-positive regulatory T cells in the colon tumors of Ido1((-/-)) mice. Importantly, 1-mT treatment also significantly altered cytokine expression in the colon tumor tissues. These results suggest that IDO inhibition alone cannot sufficiently suppress colon cancer development in mice despite its immunomodulatory activity in the tumor microenvironment.

Macroscopic on-site quality evaluation of biopsy specimens to improve the diagnostic accuracy during EUS-guided FNA using a 19-gauge needle for solid lesions: a single-center prospective pilot study (MOSE study).

BACKGROUND: Although rapid on-site cytologic evaluation provides high efficacy of EUS-guided FNA (EUS-FNA), its availability is limited. Alternatively, macroscopic on-site quality evaluation (MOSE) may increase the efficacy of EUS-FNA. OBJECTIVE: To assess the efficacy of MOSE in estimating the adequacy of histologic core specimens obtained by EUS-FNA using a standard 19-gauge needle (19GN) for solid lesions. DESIGN: A prospective pilot study. SETTING: Tertiary-care referral center. PATIENTS: One hundred patients with solid lesions (n = 111 lesions). INTERVENTIONS: EUS-FNA using 19GN MAIN OUTCOME MEASUREMENTS: The relation of a macroscopic visible core (MVC) in the FNA specimens on MOSE with histologic core and the diagnostic yields were studied. RESULTS: The feasibility of EUS-FNA using a 19GN was 99%. The final diagnoses were malignancy in 83 lesions and benign in 28. MOSE revealed MVC in 91.1% with the median length of 8 mm. Histologic core was confirmed in 78.9%. The receiver-operating characteristic curve of the length of MVC for the presence of histologic core showed the cut-off MVC length of 4 mm with area under the curve of .893. Comparisons of per-pass diagnostic yields showed significantly superior histologic, cytologic, and overall diagnostic yields in MVC ≥ 4 mm as compared with <4 mm. The multivariate analysis for false-negative pass identified lesion in the pancreas and MVC < 4 mm as significant risk factors. No adverse events were seen. LIMITATIONS: Single center, limited operators CONCLUSION: MVC of ≥4 mm on MOSE can be an indicator of specimen adequacy and can improve diagnostic yield; however, additional FNA may be recommended for pancreatic lesions. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000010417.).

IDO1 plays an immunosuppressive role in 2,4,6-trinitrobenzene sulfate-induced colitis in mice.

IDO, an enzyme that degrades the essential amino acid L-tryptophan to N-formylkynurenine, is known to exert immunomodulatory effects in a number of diseases and disorders. IDO expression is increased in tumors, where it is thought to be involved in tumor evasion by suppressing the immune response. A competitive inhibitor of IDO is currently being tested in clinical trials for relapsed or refractory solid tumors; however, there remains a concern that attenuation of the immunosuppressive function of IDO might exacerbate inflammatory responses. In this study, we investigated the role of IDO in 2,4,6-trinitrobenzene sulfate (TNBS)-induced colitis in mice by gene deletion and pharmacological inhibition. TNBS treatment induced significantly more severe colitis in Ido1 gene-deficient (Ido1⁻/⁻) mice than in Ido1 wild-type (Ido1⁺/⁺) mice, indicating a role for IDO1 in suppression of acute colitis. Consistent with this, the expression of Ido1 was increased in the colonic interstitial tissues of TNBS-treated Ido1⁺/⁺ mice. Furthermore, transplantation of Ido1⁺/⁺ bone marrow cells into Ido1⁻/⁻ mice reduced the pathological damage associated with colitis, altered the expression of cytokines, including IFN-γ, TNF-α, and IL-10, and increased the number of CD4⁺ Foxp3⁺ regulatory T cells in the colon. Pharmacological inhibition of IDO enzymatic activity by oral administration of 1-methyltryptophan (1-methyl-L-tryptophan or 1-methyl-D-tryptophan) significantly increased the severity of TNBS-induced colitis in mice, demonstrating that both stereoisomers can promote colitis. Collectively, our data indicate that IDO1 plays an important immunoregulatory role in the colon.

MR imaging findings of uterine pyomyoma: radiologic-pathologic correlation.

A 69-year-old postmenopausal female with a spontaneously occurring uterine pyomyoma was described with emphasis on the MR imaging findings. On unenhanced T1- and T2-weighted MR images, a huge mottled mass suspected to contain blood products, necrotic tissue, or purulent or viscous fluid was demonstrated within anterior myometrial wall of uterine body. The mass was surrounded by a peripheral rim that was hyperintense on T1-weighted images and hypointense on T2-weighted images. On gadolinium-enhanced MR images, most of the mass was unenhanced, but the peripheral rim was equally enhanced with the surrounding myometrium. Pathological examination revealed an intramural uterine pyomyoma surrounded by fibrous capsules with abundant lymphocytes and neutrophils. Our findings indicate that pyomyoma should be considered when MR images demonstrate a myometrial cystic lesion accompanied by a peripheral rim.

Organomagnesium suppresses inflammation-associated colon carcinogenesis in male Crj: CD-1 mice.

Magnesium (Mg) deficiency increases genomic instability and Mg intake has been reported to be inversely associated with a risk of colorectal cancer (CRC). This study was designed to determine whether organo-Mg in drinking water suppresses inflammation-associated colon carcinogenesis in mice. Male Crj: CD-1 mice were initiated with a single i.p. injection of azoxymethane (AOM, 10mg/kg body weight) and followed by a 1 week exposure to dextran sulfate sodium (DSS, 1.5%, w/v) in drinking water to induce colonic neoplasms. They were then given the drinking water containing 7, 35 or 175 p.p.m. organo-Mg for 13 weeks. The chemopreventive efficacy of organo-Mg was determined 16 weeks after the AOM exposure. Administration with organo-Mg at all doses caused a significant inhibition of CRC development (P < 0.01 and P < 0.001). Especially, the highest dose of organo-Mg significantly suppressed the occurrence of all the colonic pathological lesions (mucosal ulcer, dysplasia, adenoma and adenocarcinoma). Organo-Mg also significantly reduced the number of mitoses/anaphase bridging, as well as proliferation of CRC. Additionally, at week 4, organo-Mg lowered the messenger RNA expression of certain proinflammatory cytokines, such as interleukin-1ß, interleukin-6, interferon-γ and inducible nitric oxide synthase in the lesion-free colorectal mucosa at week 4 but increased the Nrf-2 messenger RNA expression. Our findings that organo-Mg inhibits inflammation-related mouse colon carcinogenesis by modulating the proliferative activities and chromosomal instability of CRC and suppressing colonic inflammation may suggest potential use of organo-Mg for clinical chemoprevention trials of CRC in the inflamed colon.

Galectin-3 in preneoplastic lesions of glioma.

Gliomas are the most common primary brain tumors in adults and have a poor prognosis. Galectin-3 is a ß-galactosidase-binding lectin which is important in pre-mRNA splicing, regulation of cell proliferation, cell adhesion and apoptosis. Although galectin-3 has been shown as a glioma related marker and expression of galectin-3 has been reported to correlate with WHO grade in human gliomas, expression of galectin-3 in early neoplastic lesions such as early neoplastic proliferation (ENP) and microtumor is still far from fully understood. In the present study, expression of galectin-3 in ethylnitrosourea-induced rat gliomas including preneoplastic and neoplastic lesions was examined by immunohistochemistry for galectin-3, Iba-1 (a specific microglial cell marker), GFAP (a specific astrocyte cell marker), and conventional hematoxylin and eosin staining (for morphological observation). The results showed that exact location of ENP was detected clearly by galectin-3 immunohistochemistry whereas normal brain tissues were negative. In ENP and microtumor, galectin-3 was expressed in neoplastic astrocytic cells but rarely in microglia. In malignant glioma, however, galectin-3 was expressed in both neoplastic astrocytic cells and microglia. This suggests that galectin-3 is activated in microglia and macrophages according to the progression of glioma. Galectin-3 was not expressed in oligodendrocytic cells. Our results indicate that galectin-3 is a good specific marker indicating the early stage of glioma tumorigenesis.