Tumor Testing and Genetic Analysis to Identify Lynch Syndrome Patients in an Italian Colorectal Cancer Cohort

Lynch syndrome (LS) is an inherited cancer susceptibility syndrome caused by germline mutations in a DNA mismatch repair (MMR) gene or in the EPCAM gene. LS is associated with an increased lifetime risk of colorectal cancer (CRC) and other malignancies. The screening algorithm for LS patient selection is based on the identification of CRC specimens that have MMR loss/high microsatellite instability (MSI-H) and are wild-type for BRAFV600. Here, we sought to clinically and molecularly characterize patients with these features. From 2017 to 2023, 841 CRC patients were evaluated for MSI and BRAFV600E mutation status, 100 of which showed MSI-H. Of these, 70 were wild-type for BRAFV600. Among these 70 patients, 30 were genetically tested for germline variants in hereditary cancer predisposition syndrome genes. This analysis showed that 19 of these 30 patients (63.3%) harbored a germline pathogenic or likely pathogenic variant in MMR genes, 2 (6.7%) harbored a variant of unknown significance (VUS) in MMR genes, 3 (10%) harbored a VUS in other cancer-related genes, and 6 (20%) were negative to genetic testing. These findings highlight the importance of personalized medicine for tailored genetic counseling, management, and surveillance of families with LS and other hereditary cancer syndromes.

VEGFA Status as a Predictive Marker of Therapy Outcome in Metastatic Gastric Cancer Patients Following Ramucirumab-Based Treatment

Metastatic gastric cancer (mGC) often has a poor prognosis and may benefit from a few targeted therapies. Ramucirumab-based anti-angiogenic therapy targeting the VEGFR2 represents a milestone in the second-line treatment of mGC. Several studies on different cancers are focusing on the major VEGFR2 ligand status, meaning VEGFA gene copy number and protein overexpression, as a prognostic marker and predictor of response to anti-angiogenic therapy. Following this insight, our study aims to examine the role of VEGFA status as a predictive biomarker for the outcome of second-line therapy with Ramucirumab and paclitaxel in mGC patients. To this purpose, the copy number of the VEGFA gene, by fluorescence in situ hybridization experiments, and its expression in tumor tissue as well as the density of micro-vessels, by immunohistochemistry experiments, were assessed in samples derived from mGC patients. This analysis found that amplification of VEGFA concomitantly with VEGFA overexpression and overexpression of VEGFA with micro-vessels density are more represented in patients showing disease control during treatment with Ramucirumab. In addition, in the analyzed series, it was found that amplification was not always associated with overexpression of VEGFA, but overexpression of VEGFA correlates with high micro-vessel density. In conclusion, overexpression of VEGFA could emerge as a potential biomarker to predict the response to anti-angiogenic therapy.

miR-369-3p Modulates Intestinal Inflammatory Response via BRCC3/NLRP3 Inflammasome Axis

Inflammasomes are multiprotein complexes expressed by immune cells in response to distinct stimuli that trigger inflammatory responses and the release of pro-inflammatory cytokines. Evidence suggests a different role of inflammasome NLRP3 in IBD. NLRP3 inflammasome activation can be controlled by post-translational modifications such as ubiquitination through BRCC3. The aim of this study was to investigate the effect of miR-369-3p on the expression and activation of NLRP3 inflammasomes via BRCC3 regulation. After bioinformatics prediction of Brcc3 as a gene target of miR-369-3p, in vitro, we validated its modulation in bone marrow-derived macrophages (BMDM). The increase in miR-369-3p significantly reduced BRCC3 gene and protein expression. This modulation, in turn, reduced the expression of NLRP3 and blocked the recruitment of ASC adaptor protein by NLRP3. As a result, miR-369-3p reduced the activity of Caspase-1 by the inflammasome, decreasing the cleavage of pro-IL-1β and pro-IL-18. These results support a novel mechanism that seems to act on post-translational modification of NLRP3 inflammasome activation by BRCC3. This may be an interesting new target in the personalized treatment of inflammatory disorders, including IBD.

Anaplastic Classic Kaposi Sarcoma: PD-L1 Expression and Response to Immunotherapy: A Case Report and Review of the Literature

Anaplastic classic Kaposi sarcoma (CKS) is an extremely rare pathologic variant of CKS characterized by high aggressiveness and poor prognosis. We report the clinical course of this malignant histologic form in an otherwise healthy 67-year-old male from Apulia in Southern Italy. The anaplastic progression arose during a long history of CKS and developed after multiple local and systemic treatments. The extremely aggressive and chemorefractory nature of the disease dictated amputation of a lower limb and, later, surgery for metastatic pulmonary involvement. At subsequent relapse, therapy with the anti-PD-1 inhibitor pembrolizumab was started. The immunotherapy was selected based on the PD-L1 expression in the tumor and tumor microenvironment. Remarkably, PD-1 blockade induced a complete and durable response in the patient, with a disease-free survival that has exceeded 18 months, and follow-up is still ongoing.

A Novel Mechanism of Immunoproteasome Regulation via miR-369-3p in Intestinal Inflammatory Response

The immunoproteasome is a multi-catalytic protein complex expressed in hematopoietic cells. Increased expression of immuno-subunits followed by increased proteasome activities is associated with the pathogenesis of IBD. Therefore, the identification of molecules that could inhibit the activities of this complex has been widely studied. microRNAs are small molecules of non-coding RNA that regulate the expression of target genes. Our purpose was to demonstrate that miR-369-3p is able to reduce the expression of the PSMB9 subunit and consequently modulate the catalytic activities of immunoproteasome. After bioinformatics prediction of the gene target of miR-369-3p, we validated its modulation on PSMB9 expression in the RAW264.7 cell line in vitro. We also found that miR-369-3p indirectly reduced the expression of other immunoproteasome subunits and that this regulation reduced the catalytic functions of the immunoproteasome. Increased levels of PSMB9 were observed in colon samples of acute IBD patients compared to the remission IBD group and control group. Our data suggest that miR-369-3p may be a future alternative therapeutic approach to several compounds currently used for the treatment of inflammatory disorders including IBD.

Identification of SLC15A4/PHT1 Gene Products Upregulation Marking the Intestinal Epithelial Monolayer of Ulcerative Colitis Patients

SLC15A4/PHT1 is an endolysosome-resident carrier of oligopeptides and histidine recently come into view as a key path marker of immune/autoimmune/inflammatory pathways in immune cells. Yet, its emerging role in inflammatory processes directly targeting the gastrointestinal epithelial layer, as in the multifactorial pathophysiology of inflammatory bowel disease (IBD), is poorly investigated. Here, the first identification of SLC15A4/PHT1 gene products in human colonic epithelium of ulcerative colitis (UC) patients is reported, showing protein primarily localized in intracellular vesicle-like compartments. Qualitative and quantitative immunohistochemical analyses of colon biopsies revealed overexpression of SLC15A4/PHT1 protein product in the epithelial layer of UC patients. Results were successfully mirrored in vitro, in spontaneously differentiated enterocyte-like monolayers of Caco-2 cells specifically exposed to DSS (dextran sodium sulphate) to mimic IBD inflammatory onsets. SLC15A4/PHT1 expression and cellular localization were characterized confirming its (dys)regulation traits in inflamed vs. healthy epithelia, strongly hinting the hypothesis of SLC15A4/PHT1 increased function associated with epithelial inflammation in IBD patients.

c-MYC Protein Stability Is Sustained by MAPKs in Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is the most common gastrointestinal tract malignancy. Previous reports have shown that cancerous phenotypes in the intestine are dependent on c-MYC target gene expression. Unfortunately, finding c-MYC inhibitors has proven difficult because c-MYC does not have a deep surface-binding pocket. Considering that c-MYC is maintained upregulated through β-catenin-mediated transcriptional activation and ERK-mediated post-translational stabilization, and since we have previously demonstrated that c-MYC transcriptional activation is affected by p38α as a β-catenin chromatin-associated kinase, here, we investigated p38α’s involvement in c-MYC protein stabilization in CRC. Interestingly, we found that p38α sustains c-MYC’s stability by preventing its ubiquitination and proteasomal degradation. Moreover, we showed that p38α inhibitors exhibit a synthetic lethality effect when used in combination with MEK inhibitors in CRC cells. Our findings identify p38α as a promising therapeutic target that acts on the pharmacologically “undruggable” c-MYC protein, with implications for countering c-MYC-mediated CRC proliferation, metastasization, and chemoresistance.

Abstract

c-MYC is one of the most important factors involved in colorectal cancer (CRC) initiation and progression; indeed, it is found to be upregulated in up to 80% of sporadic cases. During colorectal carcinogenesis, c-MYC is maintained upregulated through β-catenin-mediated transcriptional activation and ERK-mediated post-translational stabilization. Our data demonstrate that p38α, a kinase involved in CRC metabolism and survival, contributes to c-Myc protein stability. Moreover, we show that p38α, like ERK, stabilizes c-MYC protein levels by preventing its ubiquitination. Of note, we found that p38α phosphorylates c-MYC and interacts with it both in vitro and in cellulo. Extensive molecular analyses in the cellular and in vivo models revealed that the p38α kinase inhibitors, SB202190 and ralimetinib, affect c-MYC protein levels. Ralimetinib also exhibited a synthetic lethality effect when used in combination with the MEK1 inhibitor trametinib. Overall, our findings identify p38α as a promising therapeutic target, acting directly on c-MYC, with potential implications for countering c-MYC-mediated CRC proliferation, metastatic dissemination, and chemoresistance.

Identification and Somatic Characterization of the Germline PTEN Promoter Variant rs34149102 in a Family with Gastrointestinal and Breast Tumors

Genetic variants located in non-coding regions can affect processes that regulate protein expression, functionally contributing to human disease. Germline heterozygous mutations in the non-coding region of the PTEN gene have been previously identified in patients with PTEN hamartoma tumor syndrome (PHTS) diagnosed with breast, thyroid, and/or endometrial cancer. In this study, we report a PTEN promoter variant (rs34149102 A allele) that was identified by direct sequencing in an Italian family with a history of gastroesophageal junction (GEJ) adenocarcinoma and breast cancer. In order to investigate the putative functional role of the rs34149102 A allele variant, we evaluated the status of PTEN alterations at the somatic level. We found that PTEN protein expression was absent in the GEJ adenocarcinoma tissue of the index case. Moreover, we detected the occurrence of copy number loss involving the PTEN rs34149102 major C allele in tumor tissue, revealing that the second allele was somatically inactivated. This variant is located within an active regulatory region of the PTEN core promoter, and in silico analysis suggests that it may affect the binding of the nuclear transcription factor MAZ and hence PTEN expression. Overall, these results reveal the functional role of the PTEN promoter rs34149102 A allele variant in the modulation of PTEN protein expression and highlight its contribution to hereditary cancer risk.

Are Immunohistochemical Markers Useful in Phenotypic Gastric Cancer Classification?

To identify useful markers for prognostic and therapeutic purposes, The Cancer Genome Atlas (TCGA) provided a molecular classification of gastric cancers (GCs). Previous studies have used immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) to define immunophenotypic surrogate markers of the molecular alterations. Some critical issues concerning the correct definition of immunophenotypic groups have emerged in these studies that employed tissue microarrays (TMAs). We performed an immunophenotypic classification by evaluating MLH1, p53, HER2, E-cadherin, and Epstein-Barr virus (EBV) on the whole section of the surgical GC samples compared to most of the studies conducted on TMAs. We also investigated the immunohistochemical expression of PD-L1, a known therapeutic target. We identified the following immunophenotypic groups: EBV (2.9%); mismatch repair deficient (MMR-D) (7.2%); overexpressed p53 and/or HER2+ (61.4%); aberrant E-cadherin (11.4%); and normal pattern (17.1%). The use of surgical samples emphasized that some immunohistochemical markers were not useful for properly classifying the GC specimens. We can state that EBV (significantly correlated to PD-L1 expression) and MMR-D GCs are well-defined groups, mutually exclusive, and easily assessable with IHC and CISH, and could be candidates for immunotherapy with PD-1/PD-L1 inhibitors. As regards p53, our findings suggest that IHC assessment may be responsible for a misclassification of GC groups. Immunohistochemical evaluation of E-cadherin needs to be standardized, particularly in terms of the heterogeneous cytoplasmic/membranous staining pattern. Whether to consider the normal-pattern group as a separate category remains to be clarified. Because GC specimens with known therapeutic targets account for only 40%, we suggest reviewing the immunophenotypic classification to find new therapeutic targets, such as PD-L1, MLH1, and HER2.

Tumor microenvironment immune types in gastric cancer are associated with mismatch repair however, not HER2 status

The treatment of patients with human epidermal growth factor receptor 2 (HER2)-negative gastric cancer is a major challenge. Immunotherapy using immune checkpoint inhibitors is a rapidly growing field. In a number of malignancy types it has been demonstrated that patients with mismatch repair deficiency efficiently respond to programmed death-ligand 1 (PD-L1) blockade therapy. Recent studies have evaluated tumor microenvironment immune types to predict which patients may clinically benefit from immunotherapy. The present study aimed to evaluate the immunohistochemical expression of PD-L1 in 70 gastric cancer tissue samples. Potential associations between PD-L1 expression and mismatch repair deficiency, HER2 and Epstein Barr virus (EBV) status were then investigated in the context of the tumor microenvironment. A positive association was identified for PD-L1 expression with mismatch repair deficiency and EBV status; however, no association was revealed with HER2 status. Immunohistochemistry was then used to classify the microenvironment immune types. This demonstrated that the majority of the gastric cancer samples (73%) belonged to the tumor microenvironment immune type II [PD-L1-/cluster of differentiation 8 (CD8)+ low], which involves an immune ignorant state and has a low sensitivity to immunotherapy. However, 7% of the gastric cancer cases were identified to belong to the tumor microenvironment immune type I (PD-L1+/CD8+ high), which exhibits adaptive immune escape responses and a high chance of reversion with immune checkpoint blockade therapy. In conclusion, the present study emphasized the importance of evaluating tumor microenvironment immune types, mismatch repair deficiency status and EBV status, rather than PD-L1 expression alone, when evaluating the eligibility of a patient for immunotherapy with anti-programmed cell death protein-1/PD-L1 antibodies.

Increased nerve twigs in small intestinal mucosa with programmed cell death-ligand 1 and somatostatin receptor type 2A expression in recurrent Crohn disease: A case report

RATIONALE

Inflammatory bowel disease (IBD) patients manifest symptoms of disturbed gut function, such as neural sensory-motor changes. Programmed cell death-ligand 1 (PD-L1), normally present in neural tissue, exists in close apposition to the mucosal immune system and intestinal epithelium, and a bi-directional communication is known to occur at these interfaces. Somatostatin has been shown to suppress the inflammatory reaction, and has been used in several clinical trials to treat inflammatory disorders, such rheumatoid arthritis. Recently, somatostatin receptor type 2A, that regulates neurotransmission, proliferation, and apoptosis, has been recognized in IBD. Although prominent abnormalities in the morphology of the enteric nervous system have been observed in idiopathic IBD, they are more marked in Crohn disease.

PATIENT CONCERNS

A 55-year-old woman with recurrent Crohn disease, just surgically treated for ileal resection, have a stenotic complication.

INTERVENTIONS

At surgery 5 cm of preterminal ileum with stenosis and anastomotic ileocolic block was removed.

DIAGNOSES

The histopathology showed a recurrent Crohn in fistulo-stenotic phase; the stenosis was mainly sustained by mass-forming, ganglioneuromatous hyperplasia. Normally very rare, fine nerve twigs extend up into mucosa but we found a new-formed fibrillary network, extending into the inflammation area at the subepithelial luminal site of the mucosa, that was positive to PD-L1 and somatostatin receptor type 2A (SSTR2A) immunostaining but not visualized in routinary stained slides.

OUTCOMES

After surgery the patient was semestrally followed with clinical endoscopic evaluation that results uneventfully.

LESSONS

Our case shows that before surgery neuromatous abnormalities can be predicted by immunostained new-formed twigs in the mucosa.

PD-L1 expression in colorectal cancer defines three subsets of tumor immune microenvironments

Objectives

We investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment.

Results

PD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs.

Materials and Methods

Sixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N.

Conclusions

Our study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.

Role of PD-L1 expression as a biomarker for GEP neuroendocrine neoplasm grading

Neuroendocrine neoplasms (NENs) are rare, heterogeneous and ubiquitous tumors commonly localized in the gastrointestinal tract, lung, and pancreas. The clinical behavior of NEN is highly unpredictable; in fact, low-grade cases can unexpectedly be associated with metastases. Currently, the 2010 WHO NEN classification employs histological differentiation and the proliferation index for grading tumors but fails to provide reliable prognostic and therapeutic indications. Therefore, there is an urgent need for a better characterization of G2/G3 NENs. Similar to several other tumors, NENs possess immune-escape mechanisms, but very little has yet been done to characterize this crucial aspect. There are no available data describing PD-L1 expression in these tumors. Here we provide, for the first time, evidence of PD-L1 tissue expression in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). PD-L1 expression was significantly associated with a high-grade WHO classification (G3) (P<0.001) but not with gender, primary site, or lymph node status. The PD-L1 positivity rate and signal intensity are directly correlated (P<0.001) with a grade increase from G1 to G3. In particular in G3 cases, we observed a dichotomy between the morphology (WD- and PD-NENs) and Ki67. Moreover, our study demonstrated a significant association with the grade and PD-L1 expression levels in immune-infiltrating cells (P<0.001). In particular, G3 tumors are characterized by strong PD-L1 expression in both the tumor and infiltrating immune cells (P<0.001), reflecting an unfavorable environment for T-cell-mediated tumor aggression. These findings suggest that NENs might acquire resistance to immune surveillance by upregulating PD-L1 and inhibiting peritumoral and intratumoral infiltrating lymphocytes. Here we demonstrate that PD-L1 is currently the best-known biomarker for G3 NENs, becoming the new gold standard for G3 NEN discrimination. Furthermore, pharmacological approaches using anti-PD-1 antibodies may become the logical choice for the treatment of G3 cases with a poor prognosis.

Are biopsy specimens predictive of HER2 status in gastric cancer patients?

BACKGROUND

Trastuzumab has been recently proposed as a treatment for patients with HER2-positive advanced/metastatic gastric cancer (GC). Since most patients have inoperable disease at diagnosis, accurate assessment of HER2 status on biopsy specimens is essential to select the patients who may benefit from therapy.

AIM

The aim of this study is to establish whether HER2 status assessed on biopsy material could be reliable for treatment decisions using anti-HER2 agents.

METHODS

The HER2 status was evaluated in 61 consecutive pairs of biopsy and surgical GCs samples by immunohistochemistry and chromogenic in situ hybridization.

RESULTS

The overall concordance of HER2 status between biopsy and surgical specimens was 91.8 % with a predictive positive value of 71.4 % and a negative predictive value of 94.4 %. Of five discordant cases, there were three negative and two positive false biopsy results. All the false negative cases showed heterogeneous expression of HER2 protein in surgical samples. Two cases displayed overexpression of the receptors without corresponding gene amplification.

CONCLUSIONS

HER2 status as evaluated on biopsy samples is a fairly good predictor of HER2 status of surgically-excised GCs. The most important influence for discordant results is tumor heterogeneity. However, HER2 overexpression, especially without coexisting gene amplification, may only be a temporary change in a tumor population. This may explain those cases with positive HER2 evaluation on biopsy material and a negative result on corresponding surgical specimen.

Tissue expression of glycated apolipoprotein B in colorectal adenoma and cancer

BACKGROUND

Myocardial infarction and colorectal cancer are associated at the population level and in autoptic studies. Glycated apolipoprotein B (apoB) is a risk factor for the development of myocardial infarction. The association of glycated apoB with dysplastic and neoplastic colorectal tissue was investigated.

MATERIALS AND METHODS

Forty-eight consecutive surgical specimens, 26 colorectal adenomas and 22 colorectal carcinomas, retrieved from the archives of the Pathologic Anatomy Department of our institution, were examined. The tissue content of glycated apoB was determined using a monoclonal antibody.

RESULTS

Glycated apoB was detected in 27% of the adenomas and 45% of the cancer tissue, but only in 18% of the normal tissue near the cancer site.

CONCLUSION

Glycated apoB is associated with dysplastic and even more so with neoplastic cancer tissue.

KRAS genotyping as biomarker in colorectal cancer: a comparison of three commercial kits on histologic material

BACKGROUND/AIM

The crucial role of KRAS status in new colorectal cancer target therapy raises the issue regarding which testing method to use. This study analysed 112 formalin fixed, paraffin-embedded (FFPE) metastatic tissue samples using three different commercially available kits.

PATIENTS AND METHODS

A group of 40 KRAS wild-type (wt), 40 codon 12-mutated and 32 codon-13 mutated samples, previously evaluated by real-time PCR (TheraScreen kit), used as reference method, were analysed by Ampli-set-K-RAS and K-RAS StripAssay kit (herein called kit A and B, respectively) based on two different technologies.

RESULTS

The sensitivity of both kits was 92.5% for wt samples, 100% and 95.0% for kit A and B, respectively for samples mutated in codon 12. The specificity was 100% for both kits for all groups of samples. After a minor modification of the kit A method, its specificity reached 100%.

CONCLUSION

of low cost and easy to use, kit A may be suitable for use in a routine diagnostic setting.

EGFR-targeted therapy in colorectal cancer: does immunohistochemistry deserve a role in predicting the response to cetuximab?

The EGF receptor (EGFR) has emerged as a rational target for anticancer therapy for the treatment of colorectal cancer (CRC). Positive immunohistochemistry (IHC) staining for EGFR is used as a criterion for patient selection; however, doubt has been cast on the utility of this method. Not only is the response to cetuximab, an anti-EGFR mAb, low in patients expressing EGFRs, but a similar response to cetuximab has also been described in patients who do not express EGFRs. This review aims to evaluate the possible cause of the lack of correlation between the efficacy of cetuximab and EGFR IHC staining in CRC, as well as any modifications in the IHC method necessary to optimize patient selection for cetuximab therapy. In our opinion, the heterogeneous expression of the receptor in the neoplastic population and the inability of the mAbs used to predict the response to cetuximab could be the major cause of the failure of IHC staining as a reliable tool for patient selection. The use of specific mAbs directed against the phosphorylated and mutant form (EGFRvIII) of the EGFR could reinstate IHC as a valid predictor of response to therapy.

Parallel intestinal and liver injury during early cholestasis in the rat: modulation by bile salts and antioxidants

Whereas long-term cholestasis results in intestinal alterations and increased permeability to hepatotoxins, the effect of short-term cholestasis is less known and was investigated in bile duct ligated (BDL) rats. In the intestinal mucosa, at Day 7 BDL, total glutathione and protein sulfhydryl contents had decreased, oxidized glutathione levels increased (P<0.05 vs baseline), and a reduced epithelium thickness with dissolving crypt phenomena was observed in 40% of rats. At Day 10, total protein content, glutathione-related enzyme activities, and the transmural electrophysiological activity had decreased (-50%); by contrast, oxidized proteins doubled (P<0.05), and histological changes were extended to 70% of rats. In vitro exposure to taurodeoxycholate at micellar concentrations determined dysepithelization in normal gut but dissolving crypt phenomena and necrosis in cholestatic bowels. In the liver, ongoing cholestasis was associated with early oxidative changes especially in mitochondria, where protein sulfhydryls were decreased and negatively correlated with glutathione-protein mixed disulfides (r=-0.807, P<0.001). Daily oral administration of tauroursodeoxycholate, a hydrophilic bile salt, and glutathione to BDL rats improved intestinal histology, function, and redox state. In conclusion, short-term cholestasis results in distinctive functional, oxidative, and morphological changes of intestinal mucosa, determined increased vulnerability to toxic injury, and parallel hepatic oxidative damage.

Chemotherapeutic agents for colorectal cancer with a defective mismatch repair system: The state of the art

Mismatch repair (MMR) proteins are capable of recognizing and processing not only single base-pair mismatches and insertion-deletion loops that occur during DNA replication, but also adducts in DNA resulting from treatment with cancer chemotherapy agents. MMR deficiency leads to microsatellite instability (MSI) and results in resistance to antimetabolites, alkylating and platinating agents, DNA minor groove binders, and inhibitors of topoisomerases. Therefore, anticancer agents that can be recommended for use in MMR deficient colorectal cancers are those that exert their cytotoxicity regardless of the MMR status. These include some alkylating drugs, brostacillin, gemcytabine, photodynamic therapy, taxanes. An approach that is currently receiving much attention is the use of agents such as 5-azacytidine, an inhibitor of the DNA methyltransferases, in combination with inhibitors of histone de-acetylation, to restore the MMR function. A strong anti-proliferative efficacy with a relatively low direct cytotoxicity, obtainable with oloumicine and roscovitine (selective cyclin-dependent kinases inhibitors) can represent a new expedient for the therapeutic treatment of MMR deficient colorectal cancers. The question of how MMR defects modulate the response to chemotherapeutics deserves further investigation, to enable a more aware choice of cancer treatment.

Immunohistochemical Mismatch Repair Proteins Expression in Colorectal Cancer

Immunohistochemical (IHC) assessment of the mismatch repair proteins has been proposed as an alternative strategy to molecular biology for evaluating the unstable phenotype of tumors. With the aim of introducing IHC analysis as a routine diagnostic test, the authors compared the expression of MLH1 and MSH2 proteins with a PCR-based microsatellite assay. The concordance rate between the two methods was 90% after IHC evaluation of two different areas of each tumor. These results show that IHC may be as efficient as PCR in detecting unstable phenotype by using only one surgical or biopsy sample.

Effects of probiotic bacteria (VSL#3) on the polyamine biosynthesis and cell proliferation of normal colonic mucosa of rats

BACKGROUND

Probiotics seem to possess tumour inhibitory properties, but few studies have investigated their actions on the cell proliferation of normal colonic mucosa. The effects of a probiotic mixture (VSL#3) on polyamine biosynthesis, Ki-67 levels and apoptosis in the normal colon of rats were studied.

MATERIALS AND METHODS

For a 4-week period, 20 rats were fed a VSL#3 solution and 20 rats a saline solution. Samples from the colonic mucosa were collected at the end of treatment. Polyamines were detected by HPLC, ornithine decarboxylase activity by a radiometric technique, and apoptosis and Ki-67 by histochemical and immunohistochemical methods.

RESULTS

VSL#3 caused a significant decrease in colonic polyamine levels, ornithine decarboxylase activity and Ki-67 compared to controls. A significant increase in the apoptotic index was also observed.

CONCLUSION

Probiotics could also reduce proliferation rates in a condition not affected by hyperproliferative or neoplastic growth, when the normal control mechanisms are still completely effective.

Immunohistochemical and Serological 90K / Mac-2BP Detection in Hepatocellular Carcinoma Patients: Different Behaviour of Two Monoclonal Antibodies

To clarify the biological role of the 90K/Mac-2BP glycoprotein, we evaluated the ability of two MAbs SP-2 and 1A4.22, to reveal this glycoprotein in both serum and tissue from hepatocellular carcinoma (HCC) patients. Tissue expression of 90K was detected by the immunohistochemical method in 20 HCC patients, while the 90K serum level was assessed by the ELISA assay in 13 HCC patients. MAb SP-2 was reactive only in serum, with a mean value of 12.8+/- 6.7 microg/ml . On the contrary, MAb 1A4.22 revealed immunoreactivity both in 92% of sera and in 60% of neoplastic samples. Positive staining was seen only in the epithelial cells and was cytoplasmic and granular in all instances. The mean 90K serum level assayed with MAb 1A4.22 was 29.4 +/- 13.7 microg/ml. Patients with a 90K serum level <or= 30 microg/ml had positive tissue samples in 71% of cases versus 20% of patients with a serum level > 30 microg/ml. Moreover, a possible poor prognostic role was observed for negative 90K in tissue. Our results suggest that only MAb 1A4.22 could demonstrate 90K glycoprotein expression in paraffin-embedded tissue and that this MAb could have a diagnostic and prognostic role in both sera and tissues from HCC patients.

Ursodeoxycholate further increases bile-duct cell proliferative response induced by partial bile-duct ligation in rats

BACKGROUND

Bile salts (BSs) stimulate cholangiocyte proliferation in vitro and in vivo in normal rats. In this study, we evaluated the effects of BS-enriched diets on cholangiocyte proliferative activity already triggered by partial bile-duct ligation (pBDL), a surgical model that induces mild cholestatic conditions, focusing our attention on ursodeoxycholate (UDC).

METHODS

Animals (n=45) were fed either a standard diet, or a 0.2% deoxycholate- or 0.2% UDC-enriched diet for 4 weeks. Then, in each group, ten animals underwent pBDL and five underwent sham operation. Serum and biliary BS levels, serum cholestasis and cytolysis indexes, as well as liver conventional histology, apoptosis and proliferative activity were evaluated 48 h after the operation.

RESULTS

Animals that underwent pBDL showed sustained proliferative response compared with sham-operated rats. BS-enriched diets did not influence cholangiocyte proliferation in sham-operated rats. However, significantly increased proliferation was observed in pBDL rats fed a UDC-enriched diet. The evaluation of humoral and histological parameters excluded the possibility that the increased proliferation induced by UDC-enriched diet could be related to concomitant liver cell damage.

CONCLUSION

A UDC-enriched diet is able to amplify the magnitude of the cholangiocyte hyperplastic process, which occurs by a stimulatory mechanism after partial bile-duct ligation.

P53 and beta-catenin in colorectal cancer progression

Recently a possible cross talk about the relationship between p53 and beta-catenin has been suggested by the observation that colorectal cancers accumulating beta-catenin (as a result of APC mutations) also exhibit high frequency p53 mutations. Our aim was to evaluate the pattern of both the proteins and match these with the morphological changes in colorectal carcinogenesis. Immunohistochemical patterns of p53 and beta catenin were studied using the natural carcinogenetic model of malignant colorectal sporadic adenoma in 27 formalin-fixed paraffin-embedded polyps. We found a progressive increase of p53 and beta-catenin staining from normal, to dysplastic, and to cancerous epithelium. We noted, in dysplastic and cancerous epithelium, but not in normal tissue, the translocation of beta-catenin from the cytoplasm to the nucleus, and in dysplastic epithelium, a significant correlation between p53 over expression and beta-catenin patterns. Beta-catenin cytoplasmic accumulation seemed to drive p53 over expression already in the early stages of carcinogenesis, while nuclear beta-catenin translocation appeared to be related to a pattern of invasion of neoplastic cells.

P53 and beta-catenin in colorectal cancer progression

Recently a possible cross talk about the relationship between p53 and beta-catenin has been suggested by the observation that colorectal cancers accumulating beta-catenin (as a result of APC mutations) also exhibit high frequency p53 mutations. Our aim was to evaluate the pattern of both the proteins and match these with the morphological changes in colorectal carcinogenesis. Immunohistochemical patterns of p53 and beta catenin were studied using the natural carcinogenetic model of malignant colorectal sporadic adenoma in 27 formalin-fixed paraffin-embedded polyps. We found a progressive increase of p53 and beta-catenin staining from normal, to dysplastic, and to cancerous epithelium. We noted, in dysplastic and cancerous epithelium, but not in normal tissue, the translocation of beta-catenin from the cytoplasm to the nucleus, and in dysplastic epithelium, a significant correlation between p53 over expression and beta-catenin patterns. Beta-catenin cytoplasmic accumulation seemed to drive p53 over expression already in the early stages of carcinogenesis, while nuclear beta-catenin translocation appeared to be related to a pattern of invasion of neoplastic cells.

Evidence of apoptosis in human primordial and primary follicles

BACKGROUND

Apoptosis may operate the 'selection' between follicles destined for atresia and follicles that will remain available for ovulation. The aim of this study is to assess the expression of apoptosis in quiescent follicles.

METHODS

Ovarian cortex samples from women of reproductive age, fixed in formalin, were used for immunohistochemical and terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labelling (TUNEL) methods. In histological sections the follicles were classified as primordial, primary, secondary and antral. Follicle density was defined as the total number of follicles/0.5 cm(2) of ovarian cortical tissue. Mab DO-7 (anti-p53) and Mab 124 (anti-bcl-2) were used in the immunohistochemical study.

RESULTS

TUNEL was positive in 23.4% of the primordial follicles, and in 23.2% of the primary follicles, both in oocytes and granulosa cells, whereas all secondary follicles were negative. Bcl-2 activity was expressed in 75% of secondary follicles. p53 was negative in all samples.

CONCLUSIONS

Apoptosis could be the process responsible for atresia of quiescent follicles and hence depletion of the ovarian germ stockpile. Follicular cells expressing Bcl-2 may therefore be the viable cells that escape the apoptotic process. Negative p53 patterns may be a favourable prognostic finding showing genome integrity in the replicating follicular cells of women of reproductive age.

Mitochondrial glutathione content determines the rate of liver regeneration after partial hepatectomy in eu- and hypothyroid rats

BACKGROUND/AIMS

Mitochondrial glutathione has been postulated to affect mitochondrial function and liver regeneration.

METHODS

Mitochondrial respiration, total and oxidized glutathione, and liver regeneration were assessed after partial hepatectomy in glutathione-depleted and in hypothyroid rats with/without supplementation of glutathione ester.

RESULTS

Mitochondrial, cytosolic and circulating glutathione levels were lower in glutathione-depleted rats. Hepatectomy was followed by significant changes of intra- and extracellular glutathione and of mitochondrial respiration. In glutathione-deficient rats, the recovery of mitochondrial function and the liver regeneration were delayed. Administration of glutathione ester partially corrected the fall of cytosolic and mitochondrial glutathione following hepatectomy, reduced mitochondrial oxidative damage, and accelerated the restoration of mitochondrial respiration and the rate of liver regeneration. In hypothyroid rats, intracellular glutathione homeostasis and mitochondrial respiration were impaired already at baseline; slower regeneration and mitochondrial oxidative alterations were observed after hepatectomy. Glutathione ester ameliorated the regenerative response in hypothyroid rats by providing higher concentrations of cytosolic and mitochondrial glutathione.

CONCLUSIONS

Glutathione depletion and hypothyroidism affect the mitochondrial function during liver regeneration. Liver regenerates more slowly in glutathione-depleted and in hypothyroid rats. The earlier restoration of mitochondrial function and the higher rate of proliferation in glutathione ester treated rats suggest that the maintenance of intracellular glutathione facilitates liver regeneration.

Low presence of p53 abnormalities in H pylori-infected gastric mucosa and in gastric adenocarcinoma

BACKGROUND

Alterations of the p53 gene and/or its abnormal protein accumulation have been observed in gastric cancer and preneoplastic lesions. Our aim was to assess possible associations between different H. pylori strains and p53 abnormalities in patients with dyspepsia and with gastric cancer.

METHODS

Seventy-five dyspeptic patients and 40 patients with gastric adenocarcinoma entered the study. H. pylori status was determined by the rapid urease test, histology, and polymerase chain reaction (PCR) analysis. Overexpression of the p53 protein was evaluated by immunohistochemistry. Detection of p53 mutations was done by direct DNA sequencing.

RESULTS

Fifty-four of the 75 (72.0%) dyspeptic patients and 27 of the 40 (67.5%) gastric cancer patients showed H. pylori infection. Cytotoxin-associated gene ( cagA)-positive strains were found in 31 of the 54 (58%) dyspeptic patients and in 25 of the 27 (92.6%) neoplastic patients. As regards vacA, s2 strains showed the highest prevalence among dyspeptic patients (24 of 54 patients; 44.4%), whereas s1 strains were more expressed among cancer patients (23 of 27; 85.2%). Among the dyspeptic patients, 1 patient with duodenal ulcer showed p53 overexpression. Three mutations were identified by DNA sequencing: one in a patient with normal endoscopic findings and two in patients suffering from gastritis. Among the neoplastic patients, 16 subjects (40%) showed p53 overexpression (9 had diffuse-type and 7 intestinal-type cancer). Four mutations (10%) occurred in patients with intestinal-type gastric cancer. No association between p53 abnormalities (overexpression/mutation) and H. pylori infection was found in either group of patients.

CONCLUSIONS

These results lead us to hypothesize that H. pylori infection does not affect the p53 pattern in gastric mucosa. Moreover, mutations of the p53 gene do not seem to be a predominant event in gastric carcinogenesis, at least in our populations.

Influence of ursodeoxycholate-enriched diet on liver tumor growth in HBV transgenic mice

Hepatitis B virus (HBV) transgenic mice (official designation, Tg [Alb-1 HBV] Bri 44) invariably develop macroscopically evident tumors within the 20th month of life. Sustained proliferative activity seems to play an important role in the development of these lesions. We previously showed that ursodeoxycholate (UDC) stimulates hepatocyte proliferation in various experimental settings. Herein, we tested the assumption that biological factors able to further increase liver cell proliferation, such as UDC, could accelerate tumor development in this animal model. For this study, 22 eight-week-old male transgenic mice were divided into 2 groups; 11 animals received a standard diet, and 11 received a UDC-enriched diet. The 2 groups were further divided into 2 subgroups of 5 and 6 animals each and were sacrificed at 3 and 15 months of age, respectively. These different times were chosen to exclude diet-related toxicity (in 3-month-old mice) and evaluate tumor growth (in 15-month-old mice). In addition, hepatocyte proliferation was assessed in all animals. In 3-month-old mice receiving UDC, cholestatic and cytolytic indices as well as liver histology were comparable to those in controls. At 15 months, all UDC-treated mice showed large multinodular tumors whereas only 33% of controls developed smaller uninodular neoplasms. Hepatocyte proliferation was increased in all animals receiving UDC compared with controls. In conclusion, the increase in serum UDC (undetectable in mice fed a standard diet), in the absence of any toxic effect on the liver, suggests the involvement of this bile salt in the stimulation of hepatocyte proliferation and tumor growth.

Mismatch repair, p53 and beta-catenin proteins in colorectal cancer

BACKGROUND

Mismatch repair (MMR) proteins (MSH2 and MLH1) deficiency is responsible for microsatellite instability (MSI) status. We evaluated p53 and beta-catenin expressions in colorectal cancer specimens with known microsatellite status, previously assessed by means of the polymerase chain reaction (PCR). We also analyzed the MMR proteins immunostaining and compared the results with those ascertained by PCR.

MATERIALS AND METHODS

Twenty-five colorectal cancer patients were analyzed for immunohistochemical expression of p53, beta-catenin, MSH2 and MLH1 proteins.

RESULTS

The microsatellite status was only significantly correlated with p53 expression and MRR proteins pattern.

CONCLUSION

We demonstrated a significantly higher p53 expression in MSI colorectal specimens. The concordance rate between immunohistochemistry and PCR was so high (80%) that the immunohistochemical technique can be proposed as a method to select MSI patients for improved outcome and response to chemotherapy.

Demonstration of a direct stimulatory effect of bile salts on rat colonic epithelial cell proliferation

BACKGROUND

Despite the clear demonstration that an increase in faecal bile salt concentration can augment colonocyte proliferation, it is still controversial whether bile salts act on these cells as direct mitogens or by inducing a damage-related proliferative response. The goal of this study was to define the mechanism mediating the proliferative effect of bile salts on rat colonocytes.

METHODS

Faecal bile salt concentration was increased by feeding rats on diets enriched with either bile salts or fats. Colonic mucosa proliferating cell nuclear antigen (PCNA) expression, histology and apoptosis, and faecal water cytolytic activity were evaluated to assess proliferation and direct or indirect signs of mucosal damage.

RESULTS

Compared to standard diet, chenodeoxycholate-, deoxycholate- and fat-enriched diets produced a significant increase in both faecal water total bile salt concentration (46.0 versus 124.1, 145.9 and 498.5 micromol/L, respectively) and percentage of PCNA-positive nuclei (30.5, versus 37.7, 33.9 and 47.1, respectively) that appeared significantly correlated (r = 0.8; P < 0.001). Chenodeoxycholate and deoxycholate fed animals showed colonic mucosa histology and faecal water cytolytic activity similar to controls, with a significantly reduced apoptotic index. Rats fed on high fat diet, however, showed a mild inflammatory infiltrate associated with an increased apoptosis and faecal water cytolytic activity, all conditions not apparently determined by the increased faecal water total bile salt concentration.

CONCLUSIONS

The results obtained in this study demonstrate that bile salts act as direct mitogens on colonic epithelial cells.

Increased oxidative stress in dimethylnitrosamine-induced liver fibrosis in the rat: effect of N-acetylcysteine and interferon-alpha

Oxidative stress may represent a common link between chronic liver damage and hepatic fibrosis. Antioxidants and interferon seem to protect against hepatic stellate cell (HSC) activation and liver fibrosis. This study evaluated (1) the effect of the profibrotic agent dimethylnitrosamine (DMN) on the hepatic oxidative balance in the rat; (2) the role played by the antioxidant agent N-acetylcysteine (NAC); and (3) the antifibrotic effects of two different types of interferon-alpha: recombinant alpha-2b (rIFN-alpha) and leukocyte alpha (LeIFN-alpha). Five groups of rats received: (1) saline; (2) DMN; (3) DMN + NAC; (4) DMN + rIFN-alpha; and (5) DMN + LeIFN-alpha. Oxidative balance was evaluated by hepatic glutathione, TBARs, protein carbonyl, and sulfhydryl determination. Fibrosis was determined by hepatic hydroxyproline content and fibronectin (FN) staining (immunohistochemistry). DMN rats showed a diffuse FN deposition, an impaired oxidative balance, and higher hepatic hydroxyproline levels compared to that of controls. NAC administration significantly reduced FN deposition, increased hepatic glutathione, and decreased TBARs and protein carbonyls. Administration of IFN-alpha exerted different effects according to the type used. Both IFNs decreased FN deposition; however, LeIFN-alpha significantly improved histology and oxidative parameters compared to those of untreated DMN and rats treated with rIFN-alpha. This study shows the role of free radicals in this model of hepatic fibrosis; the protective effect of NAC against liver fibrosis; and the antifibrotic effect exerted by IFN-alpha (particularly LeIFN-alpha) independent of its antiviral activity.

Immunohistochemical reactivity of anti-melanoma monoclonal antibody 225.28S in human breast cancer biopsies

The high molecular weight melanoma-associated antigen, defined by murine monoclonal antibody (IgG1) 225.28S is largely expressed by melanoma cells and weakly expressed by other human tumors originating from neural crest. In this study, we analyzed the immunohistochemical reactivity of MoAb 225.28S in human breast cancer biopsies. A total of 92 breast cancer biopsies (66 infiltrating lobular and 26 infiltrating ductal carcinomas) were initially tested along with 26 melanomas (positive controls), 23 gastric/colonic adenocarcinomas and 13 neuroendocrine tumors. Forty-four out of 66 lobular breast carcinomas showed positive immunostaining with 225.28S MoAb as well as only 6 out of 26 infiltrating ductal histotype and 12 out of 26 melanomas. Conversely, gastric and colonic adenocarcinomas and neuroendocrine tumors were completely negative. The pattern of positivity in breast carcinomas was associated with malignant cells, rather than with the stroma or histiocytes infiltrating the lesions. Nonspecific cross-reactivity of 225.28S with breast carcinomas was excluded using a similar murine antithyreoglobulin MoAb, which gave negative staining in all biopsies. These results indicated that HMW-MAA or a similar sequence recognized by 225.28S MoAb is often expressed by lobular breast carcinomas but rarely by ductal adenocarcinomas. This seems to suggest that lobular breast carcinoma has common "ancestor" antigens with melanoma.

Overexpression of p53 in a large series of patients with hepatocellular carcinoma: a clinicopathological correlation

p53 mutant protein has been found in a variety of human malignancies. In order to assess the controversial role of p53 protein in hepatocellular carcinoma (HCC) we studied its immunohistochemical expression in a series of 193 HCC specimens. Positive immunostaining for p53 was detected in the nuclei of neoplastic cells of 29 (15%) HCCs. There was no immunohistochemical evidence of mutant p53 expression either in normal or cirrhotic tissue surrounding neoplastic tissue. Higher alphafetoprotein serum levels were significantly associated with p53 overexpression. A prevalence of p53+ HCC specimens was seen in HCV negative patients (36% vs 13%, p < 0.05). No statistically significant correlations between p53 overexpression, age, sex, and HBV infection status were found. As regards histological grading, p53 was detected more frequently in tumours with poor cellular differentiation, although this finding does not reach statistical significance. The p53+ HCC rate was comparable to that attributed to the low incidence areas for HCC, in epidemiological studies. Moreover, p53 mutation seems to be related to the reactivation of alphafetoprotein gene to a more aggressive phenotype and to a later stage of liver carcinogenesis.

Programmed cell death in colorectal carcinogenesis

The most studied mechanism of malignant transformation has been cell proliferation. The relationship between programmed cell death (apoptosis), cell proliferation, and apoptosis regulatory genes (p53 and bcl-2), was studied in normal colonic epithelium, 26 sporadic adenomas both early and late, 25 FAP adenomas, and 34 carcinomas. We showed a decrease in programmed cell death and an increase in cell proliferation during the transition from adenoma to carcinoma. The increase of expression of p53 from early (10%) to late adenomas (87%) contrasted with the decrease of bcl-2 staining. Sixty-two per cent and 23% of carcinomas were reactive for p53 and bcl-2 respectively. Abnormal early activation of the bcl-2 gene, rather than late p53 gene mutation appears to be responsible for inhibition of apoptosis in colorectal carcinogenesis. bcl-2 was higher in FAP adenomas than in sporadic cases, and in carcinomas favouring the accumulation of long-living cells, which are more subject to mutation and thus cancerization.

Different human papillomavirus genotypes in ano-genital lesions

In order to verify the frequency and physical state of some viral strains of Human Papillomavirus (HPV) in anogenital lesions, two-hundred and four specimens were studied. HPV/DNA was detected by using non isotopic in situ hybridization method, HPV-DNA was found in 25 lesions. The integrated pattern of HPV types 16/18 was found only in invasive carcinomas, the episomic one in all high risk lesions, never in invasive carcinomas. The low oncogenic risk genotypes 6/11 were detected only in condylomata acuminata, the high oncogenic risk genotypes 16/18 were found not only in cervical intraepithelial and invasive lesions, but also in a condyloma acuminatum. Our findings confirm the importance of the viral genotypes in the evaluation of the risk for malignancy. Therefore, the detection of a high risk viral genotype, independently of its physical state, can evoke the ghost of the malignancy also in a low risk cervical lesion.

Immunohistochemical detection of p53 protein in anogenital lesions and its relationship with HPV status

The p53 tumour suppressor protein can be rendered ineffective by mutations in the p53 gene or by interactions with proteins of DNA-transforming viruses, including Human Papillomaviruses (HPVs). Our aim was to determine whether the inactivation of p53, caused by a mutation of gene itself or by HPV is involved in anogenital carcinogenesis. We studied p53 overexpression by immunohistochemical methods, and HPV/DNA by non isotopic in situ hybridization method in 137 anogenital lesions. Immunoreactivity for p53 was seen in 5% of condylomata acuminata, in 12% of low-grade CINs, in 3.5% of high-grade CINs, and in 17% of invasive cervical carcinomas. Two (67%) of three condylomata acuminate p53+ harboured HPV/DNA. The concomitant presence of p53 and HPV was not detected in intraepithelial and invasive cervical lesions. Our findings suggest that p53 inactivation does not seem to play an important role in anogenital carcinogenesis. Further investigation of the concomitant presence of p53 and HPV in condylomata acuminate and its role in recurrences or progression of these lesions is needed.

Investigative burying by laboratory mice may involve non-functional, compulsive, behaviour

The burying activity levels of albino mice offered a glass marble and a living scorpion on different occasions, were compared with the levels of exploration/investigation, avoidance, and displacement activities the same subjects performed during these and two other tests, the latter involving exploration with no particular stimulus-object and displacement with locomotion impossible. Although different average response levels were expected to occur in the different tests, it was assumed that the levels of related behavioural patterns correlated over the variation of individual mice. The scorpion elicited more burying than the marble, but the inanimate stimulus-object caused more avoidance. Exploration produced the only consistent, positive, correlation with burying in both female and male subjects. Only negative correlation occurred in males between burying and displacement, suggesting that these were alternative, in part non-functional, patterns. In females and males, while both touching and avoiding the marble decreased with experience over days, burying and displacement did not. The main conclusion is that burying began as an appropriate, investigative, activity, but, following frustrated investigation of the non-reactive stimulus-object, persisted as a compulsive stereotypy in subjects lacking in general experience, as laboratory rodents are in comparison with wild conspecifics. A simple model of compulsive disorder is proposed, in which initially appropriate behaviour goes on with inappropriate repetition when it does not attain its aim and the subject has internal difficulty in finding alternative patterns.

Localization of p53 protein and human papillomavirus in laryngeal squamous lesions

The p53 tumour suppressor protein can be ineffective because of mutations in the p53 gene or interactions with proteins synthesized by specific subtypes of HPV. We investigated the localization of p53 protein in association with HPV in paraffin sections of 10 dysplastic and 12 malignant laryngeal squamous epithelium specimens by using immunohistochemical and in situ hybridization techniques. Viral HPV type 16 or 18 related sequences were identified only in a squamous cell carcinoma (SCC) specimen. p53 was detected in 64% of cases studied. All p53+ specimens showed no HPVrelated sequences; the only HPV+ case was p53 negative. In our study, the increased p53 expression in the process from dysplastic to invasive SCC indicates that p53 overexpression is an early event in laryngeal carcinogenesis. Moreover, the systemic susceptibility to HPV infection suggests the need for an accurate evaluation of SCC risk not only in the genital tract in female patients shown to be positive for transforming HPV types (16 or 18).

Immunohistochemical p53 overexpression correlated to c-erbB-2 and cathepsin D proteins in colorectal cancer

The immunohistochemical overexpression of p53 protein in 42 large bowel cancers was correlated to c-erbB-2, cathepsin D (CD) proteins and other clinical and prognostic parameters. p53 overexpression (found in 60% of specimens) was positively associated with cathepsin D staining in stromal cells from older patients and better differentiated colorectal carcinomas (G1 + G2). Cytoplasmatic staining of c-erbB-2 protein was found in 58% of cases. No staining was observed at the cell membrane level. Our findings suggest that lower p53 expression in G3 carcinomas may be due to a high genomic instability, with the loss of both alleles of the gene. Therefore, these carcinomas were immunohistochemically silent. Although our series was small, the association between p53 nuclear neoplastic cells and CD stromal cells is interesting as regards the possible implications of these markers in colorectal cancer.

The immunohistochemical expression of cathepsin D in colorectal cancer

It has been suggested that cathepsin D expression in stromal cells affects the prognosis of breast cancer. With reference to colon and breast cancer, this study verified cathepsin D immunostaining in epithelial and stromal cells of primary tumours and lymph-node metastases from 46 colorectal carcinomas. Eight of 46 cases (17%) were cathepsin D+ both in cancer and stromal cells. No staining was found either in cancer or stromal cells of the remaining cases. The results presented here suggest the possible paracrine influence of another diffusible factor produced by cancer cells which stimulates cathepsin D production in stromal and cancer cells.

P-170 glycoprotein expression in gastric and colorectal carcinomas and normal mucosa. An immunocytochemical study

During the past few years it has become apparent that simultaneous resistance of tumour cells to a number of heterocyclic drugs (multidrug resistance) is often correlated with overexpression of a P-glycoprotein (P-gp or P-170). P-gp expression can be studied by molecular biology and immunohistochemical techniques. The latter provide a rapid, sensitive and specific screening method suitable for testing even a relatively small number of tumour cells like those obtained at biopsy. The aim of this study was to detect and localize the immunohistochemical expression of P-gp in normal and neoplastic gastrointestinal tissue using the Mab JSB-1 in formalin-fixed paraffin-embedded specimens. A particularly striking finding of our study was the consistent, prevalent higher expression of P-gp in the stomach than in the colon, with a higher percentage of immunostaining in normal than in neoplastic tissue. This is in agreement with the fact that not only is the prognosis known to be worse for stomach cancer, but also the response to treatment is lower. Further studies should be carried out to verify the possibility of making routine tests of this kind for the evaluation of multidrug resistance, to guide the selection of patients for treatment of cancer with chemotherapeutic drugs.

Composite carcinoid-adenocarcinoma of the stomach associated with multiple gastric carcinoids and nonantral gastric atrophy

A case of multiple gastric carcinoids and nonantral atrophic gastritis in which the larger tumor was a composite carcinoid-adenocarcinoma is presented. The two components of the composite tumor immunohistochemically showed clear-cut diverging functional differentiations although the available evidence supported a common histogenesis from the metaplastic intestinal epithelium of the gastric mucosa. The carcinoid tissue of the composite tumor, which showed "atypical" features, also differed from the other, pure carcinoids, in which the histologic appearance was "typical." Total gastrectomy performed 1 month after the original gastric resection with antrectomy disclosed regressive changes in the endocrine cell proliferations of the gastric stump consistent with the withdrawal of a stimulating effect of the antral gastrin.

[Vertebral fracture caused by electric cardioversion]

A case of vertebral fracture following DC shock for ventricular fibrillation is reported. After a short review of the complications of this procedure the case is described and compared with two other cases known in literature. We conclude that, although this complication is uncommon, it must be kept in mind owing to its potential severity.