Young-onset colorectal cancer is associated with a personal history of type 2 diabetes

BACKGROUND

Colorectal cancer (CRC) is rising in incidence in young adults, and this observation is currently unexplained. We investigated whether having a personal history of type 2 diabetes mellitus (T2D) was a potential risk factor for young-onset colorectal cancer (YOCRC).

METHODS

The South Australian Young Onset (SAYO) CRC study is a series of young adults with CRC below age 55. Ninety unrelated YOCRC cases were recruited to the study. Personal history and detailed family history of T2D were obtained at face-to-face interview and confirmed from medical records. Whole exome sequencing was conducted on germline DNA from each CRC case. Controls for personal history studies of T2D were 240 patients with proven clear colonoscopies and no known CRC predispositions.

RESULTS

The median age of YOCRC cases was 44 years (18-54) and of controls was 45 years (18-54), and 53% of both cases and controls were females (P = 0.99). Left-sided (distal) CRC was seen in 67/89 (75%) of cases. A personal history of T2D was confirmed in 17/90 (19%) YOCRC patients compared with controls (12/240, 5%; P < 0.001; odds ratio = 4.4; 95% confidence interval, 2.0-9.7). YOCRC patients frequently reported at least one first-degree relative with T2D (32/85, 38%). Ten of 87 (12%) of YOCRC cases had CRC-related pathogenic germline variants, however, no pathogenic variants in familial diabetes-associated genes were seen.

CONCLUSIONS

Though the mechanism remains unclear, our observations suggest that there is enrichment for personal history of T2D in YOCRC patients.

IMPACT

A diagnosis of T2D could therefore potentially identify a subset of young adults at increased risk for CRC and in whom early screening might be appropriate.

Myofibroblast androgen receptor expression determines cell survival in co-cultures of myofibroblasts and prostate cancer cells in vitro

Fibroblasts express androgen receptor (AR) in the normal prostate and during prostate cancer development. We have reported that loss of AR expression in prostate cancer-associated fibroblasts is a poor prognostic indicator. Here we report outcomes of direct and indirect co-cultures of immortalised AR-positive (PShTert-AR) or AR-negative (PShTert) myofibroblasts with prostate cancer cells.

In the initial co-cultures the AR-negative PC3 cell line was used so AR expression and signalling were restricted to the myofibroblasts. In both direct and indirect co-culture with PShTert-AR myofibroblasts, paracrine signalling to the PC3 cells slowed proliferation and induced apoptosis. In contrast, PC3 cells proliferated with PShTert myofibroblasts irrespective of the co-culture method. In direct co-culture PC3 cells induced apoptosis in and destroyed PShTerts by direct signalling. Similar results were seen in direct co-cultures with AR-negative DU145 and AR-positive LNCaP and C4-2B prostate cancer cell lines. The AR ligand 5α-dihydrotestosterone (DHT) inhibited the proliferation of the PShTert-AR myofibroblasts, thereby reducing the extent of their inhibitory effect on cancer cell growth.

These results suggest loss of stromal AR would favour prostate cancer cell growth in vivo, providing an explanation for the clinical observation that reduced stromal AR is associated with a poorer outcome.

Fibroblasts derived from oesophageal adenocarcinoma differ in DNA methylation profile from normal oesophageal fibroblasts

Oesophageal adenocarcinoma (OAC) is increasing in incidence and has a poor prognosis. Tumour derived fibroblasts (TDFs) differ functionally from normal fibroblasts (NDFs), and play a pivotal role in cancer. Many of the differences persist through subculture. We measured the DNA methylation profiles of 10 TDFs from OAC with 12 NDF from normal oesophageal mucosa using Infinium HumanMethylation450 Beadchips and found they differed in multidimensional scaling analysis. We identified 4,856 differentially methylated CpGs (DMCs, adjusted p < 0.01 and absolute difference in average β-value > 0.15), of which 3,243 (66.8%) were hypomethylated in TDFs compared to NDFs. Hypermethylated DMCs were enriched at transcription start sites (TSSs) and in CpG islands, and depleted in transcriptional enhancers. Gene ontology analysis of genes with DMCs at TSSs revealed an enrichment of genes involved in development, morphogenesis, migration, adhesion, regulation of processes and response to stimuli. Alpha-smooth muscle actin (α-SMA) is a marker of activated fibroblasts and a poor prognostic indicator in OAC. Hypomethylated DMCs were observed at the TSS of transcript variant 2 of α-SMA, which correlated with an increase in α-SMA protein expression. These data suggest that DNA methylation may contribute to the maintenance of the TDF phenotype.

Androgen Signaling in Esophageal Adenocarcinoma Cell Lines In Vitro

BACKGROUND

We showed previously that nuclear localization of the androgen receptor (AR) and expression of the androgen-responsive gene FK506-binding protein 5 (FKBP5) in esophageal adenocarcinoma (EAC) tissues were associated with decreased patient survival, suggesting a role for androgens in this cancer.

AIM

To investigate the effect of the AR ligand 5α-dihydrotestosterone (DHT) on AR-expressing EAC cell lines in vitro.

METHODS AND RESULTS

In tissue resection specimens from EAC patients, FKBP5 expression was positively associated with proliferation as measured by Ki-67 expression. We stably transduced AR into three AR-negative EAC cell lines, OE33, JH-EsoAd1, and OE19, to investigate androgen signaling in vitro. In the AR-expressing cell lines, 10 nM DHT, the concentration typically used to study AR signaling, induced changes in the expression of androgen-responsive genes and inhibited proliferation by inducing cell cycle arrest and senescence. At lower DHT concentrations near the half maximal inhibitory concentration (IC50), the AR-expressing cell lines proliferated and there were changes in the expression of androgen-responsive genes. In direct co-culture with cancer-associated fibroblast-like PShTert myofibroblasts, 10 nM DHT induced changes in the expression of androgen-responsive genes but did not inhibit proliferation.

CONCLUSIONS

This is the first study to show that EAC cell lines respond to androgen in vitro. Proliferation together with the expression of androgen-responsive genes was dependent on the concentration of DHT, or the presence of a permissive microenvironment, consistent with observations in the tissues. These findings are consistent with a role for androgen signaling in EAC.

Stromal androgen receptor regulates the composition of the microenvironment to influence prostate cancer outcome

Androgen receptor (AR) signaling in stromal cells is important in prostate cancer, yet the mechanisms underpinning stromal AR contribution to disease development and progression remain unclear. Using patient-matched benign and malignant prostate samples, we show a significant association between low AR levels in cancer associated stroma and increased prostate cancer-related death at one, three and five years post-diganosis, and in tissue recombination models with primary prostate cancer cells that low stromal AR decreases castration-induced apoptosis. AR-regulation was found to be different in primary human fibroblasts isolated from adjacent to cancerous and non-cancerous prostate epithelia, and to represent altered activation of myofibroblast pathways involved in cell cycle, adhesion, migration, and the extracellular matrix (ECM). Without AR signaling, the fibroblast-derived ECM loses the capacity to promote attachment of both myofibroblasts and cancer cells, is less able to prevent cell-matrix disruption, and is less likely to impede cancer cell invasion. AR signaling in prostate cancer stroma appears therefore to alter patient outcome by maintaining an ECM microenvironment inhibitory to cancer cell invasion. This paper provides comprehensive insight into AR signaling in the non-epithelial prostate microenvironment, and a resource from which the prognostic and therapeutic implications of stromal AR levels can be further explored.

The expression of tachykinin receptors in the human lower esophageal sphincter

Mammalian tachykinins are a family of neuropeptides which are potent modulators of smooth muscle function with a significant contractile effect on human smooth muscle preparations. Tachykinins act via three distinct G protein-coupled neurokinin (NK) receptors, NK1, NK2 and NK3, coded by the genes TACR1, TACR2 and TACR3 respectively. The purpose of this paper was to measure the mRNA and protein expression of these receptors and their isoforms in the clasp and sling fibers of the human lower esophageal sphincter complex and circular muscle from the adjacent distal esophagus and proximal stomach. We found differences in expression between the different receptors within these muscle types, but the rank order of the receptor expression did not differ between the different muscle types. The rank order of the mRNA expression was TACR2 (α isoform)>TACR2 (β isoform)>TACR1 (short isoform)>TACR1 (long isoform)>TACR3. The rank order of the protein expression was NK2>NK1>NK3. This is the first report of the measurement of the transcript and protein expression of the tachykinin receptors and their isoforms in the muscles of the human lower esophageal sphincter complex. The results provide evidence that the tachykinin receptors could contribute to the regulation of the human lower esophageal sphincter, particularly the TACR2 α isoform which encodes the functional isoform of the tachykinin NK2 receptor was the most highly expressed of the tachykinin receptors in the muscles associated with the lower esophageal sphincter.

Investigation of cholecystokinin receptors in the human lower esophageal sphincter

AIM: To compare the binding of cholecystokinin (CCK)-8 to CCK receptors in sling and clasp fibers of the human lower esophageal sphincter.

METHODS: Esophageal sling and clasp fibers were isolated from eight esophagectomy specimens, resected for squamous cell carcinoma in the upper two thirds of the esophagus, which had been maintained in oxygenated Kreb’s solution. Western blot was used to measure CCK-A and CCK-B receptor subtypes in the two muscles. A radioligand binding assay was used to determine the binding parameters of ³H-CCK-8S to the CCK receptor subtypes. The specificity of binding was determined by the addition of proglumide, which blocks the binding of CCK to both receptor subtypes.

RESULTS: There was no significant difference between the sling and clasp fibers of the human lower esophageal sphincter in the amount of CCK-A [integrated optical density (IOD) value: 22.65 ± 0.642 vs 22.328 ± 1.042, P = 0.806] or CCK-B receptor protein (IOD value: 13.20 ± 0.423 vs 12.45 ± 0.294, P = 0.224) as measured by Western blot. The maximum binding of radio-labeled CCK-8S was higher in the sling fibers than in the clasp fibers (595.75 ± 3.231 cpm vs 500.000 ± 10.087 cpm, P < 0.001) and dissociation constant was lower (K_d: 1.437 ± 0.024 nmol/L vs 1.671 ± 0.024 nmol/L, P < 0.001). The IC₅₀ of the receptor specific antagonists were lower for the CCK-A receptors than for the CCK-B (P < 0.01).

CONCLUSION: CCK binding modulates the contractile function of the lower esophageal sphincter through differential binding to the CCK-A receptor on the sling and clasp fibers.

Identification of an enhancer that increases miR-200b~200a~429 gene expression in breast cancer cells

The miR-200b~200a~429 gene cluster is a key regulator of EMT and cancer metastasis, however the transcription-based mechanisms controlling its expression during this process are not well understood. We have analyzed the miR-200b~200a~429 locus for epigenetic modifications in breast epithelial and mesenchymal cell lines using chromatin immunoprecipitation assays and DNA methylation analysis. We discovered a novel enhancer located approximately 5.1kb upstream of the miR-200b~200a~429 transcriptional start site. This region was associated with the active enhancer chromatin signature comprising H3K4me1, H3K27ac, RNA polymerase II and CpG dinucleotide hypomethylation. Luciferase reporter assays revealed the upstream enhancer stimulated the transcription of the miR-200b~200a~429 minimal promoter region approximately 27-fold in breast epithelial cells. Furthermore, we found that a region of the enhancer was transcribed, producing a short, GC-rich, mainly nuclear, non-polyadenylated RNA transcript designated miR-200b eRNA. Over-expression of miR-200b eRNA had little effect on miR-200b~200a~429 promoter activity and its production did not correlate with miR-200b~200a~429 gene expression. While additional investigations of miR-200b eRNA function will be necessary, it is possible that miR-200b eRNA may be involved in the regulation of miR-200b~200a~429 gene expression and silencing. Taken together, these findings reveal the presence of a novel enhancer, which contributes to miR-200b~200a~429 transcriptional regulation in epithelial cells.

Epigenetic modulation of the miR-200 family is associated with transition to a breast cancer stem-cell-like state

The miR-200 family is a key regulator of the epithelial-mesenchymal transition, however, its role in controlling the transition between cancer stem-cell-like and non-stem-cell-like phenotypes is not well understood. We utilized immortalized human mammary epithelial (HMLE) cells to investigate the regulation of the miR-200 family during their conversion to a stem-like phenotype. HMLE cells were found to be capable of spontaneous conversion from a non-stem to a stem-like phenotype and this conversion was accompanied by the loss of miR-200 expression. Stem-like cell fractions isolated from metastatic breast cancers also displayed loss of miR-200 indicating similar molecular changes may occur during breast cancer progression. The phenotypic change observed in HMLE cells was directly controlled by miR-200 because restoration of its expression decreased stem-like properties while promoting a transition to an epithelial phenotype. Investigation of the mechanisms controlling miR-200 expression revealed both DNA methylation and histone modifications were significantly altered in the stem-like and non-stem phenotypes. In particular, in the stem-like phenotype, the miR-200b-200a-429 cluster was silenced primarily through polycomb group-mediated histone modifications whereas the miR-200c-141 cluster was repressed by DNA methylation. These results indicate that the miR-200 family plays a crucial role in the transition between stem-like and non-stem phenotypes and that distinct epigenetic-based mechanisms regulate each miR-200 gene in this process. Therapy targeted against miR-200 family members and epigenetic modifications might therefore be applicable to breast cancer.

Characterization of excitatory and inhibitory motor neurons to the human gastric clasp and sling fibers

The aim of this study was to determine the morphology and position of the excitatory and inhibitory motor neurons to the human gastric sling and clasp fibers. Motor neurons were identified by retrograde staining with 1,1'-didodecyl 3,3,3',3'-indocarbocyanine perchlorate (DiI), and choline acetyltransferase (ChAT) or nitric oxide synthase (NOS) immunoreactivity was then determined in these motor neurons. In the sling preparations, 46% of the DiI-stained cells were aboral motor neurons, 43% were local motor neurons, and only 10% were descending motor neurons. Overall, 58% were immunoreactive for ChAT, and 36% for NOS (P = 0.042). Sixty-two percent of local, and 66% of aboral DiI-stained motor neurons were immunoreactive for ChAT. In the clasp preparations, 52% of the DiI-stained cells were descending motor neurons, 45% were local motor neurons, and only 3% were aboral neurons. Overall, 31% were immunoreactive for ChAT and 65% for NOS (P = 0.039). Eighty-five percent of the DiI-stained descending motor neurons were immunoreactive for NOS. All of the cells that were labeled adequately had a single axon and a number of filamentous or flattened lobular dendrites, and fitted into the broad category of Dogiel type I neurons. In conclusion, the majority of the motor neurons to the sling fibers were ChAT-positive excitatory neurons from the myenteric plexus of the stomach and the local region, and to the clasp were predominantly NOS-positive inhibitory neurons from the esophagus.

Whole genome expression array profiling highlights differences in mucosal defense genes in Barrett's esophagus and esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) has become a major concern in Western countries due to rapid rises in incidence coupled with very poor survival rates. One of the key risk factors for the development of this cancer is the presence of Barrett's esophagus (BE), which is believed to form in response to repeated gastro-esophageal reflux. In this study we performed comparative, genome-wide expression profiling (using Illumina whole-genome Beadarrays) on total RNA extracted from esophageal biopsy tissues from individuals with EAC, BE (in the absence of EAC) and those with normal squamous epithelium. We combined these data with publically accessible raw data from three similar studies to investigate key gene and ontology differences between these three tissue states. The results support the deduction that BE is a tissue with enhanced glycoprotein synthesis machinery (DPP4, ATP2A3, AGR2) designed to provide strong mucosal defenses aimed at resisting gastro-esophageal reflux. EAC exhibits the enhanced extracellular matrix remodeling (collagens, IGFBP7, PLAU) effects expected in an aggressive form of cancer, as well as evidence of reduced expression of genes associated with mucosal (MUC6, CA2, TFF1) and xenobiotic (AKR1C2, AKR1B10) defenses. When our results are compared to previous whole-genome expression profiling studies keratin, mucin, annexin and trefoil factor gene groups are the most frequently represented differentially expressed gene families. Eleven genes identified here are also represented in at least 3 other profiling studies. We used these genes to discriminate between squamous epithelium, BE and EAC within the two largest cohorts using a support vector machine leave one out cross validation (LOOCV) analysis. While this method was satisfactory for discriminating squamous epithelium and BE, it demonstrates the need for more detailed investigations into profiling changes between BE and EAC.

An autocrine TGF-beta/ZEB/miR-200 signaling network regulates establishment and maintenance of epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a form of cellular plasticity that is critical for embryonic development and tumor metastasis. A double-negative feedback loop involving the miR-200 family and ZEB (zinc finger E-box-binding homeobox) transcription factors has been postulated to control the balance between epithelial and mesenchymal states. Here we demonstrate using the epithelial Madin Darby canine kidney cell line model that, although manipulation of the ZEB/miR-200 balance is able to repeatedly switch cells between epithelial and mesenchymal states, the induction and maintenance of a stable mesenchymal phenotype requires the establishment of autocrine transforming growth factor-β (TGF-β) signaling to drive sustained ZEB expression. Furthermore, we show that prolonged autocrine TGF-β signaling induced reversible DNA methylation of the miR-200 loci with corresponding changes in miR-200 levels. Collectively, these findings demonstrate the existence of an autocrine TGF-β/ZEB/miR-200 signaling network that regulates plasticity between epithelial and mesenchymal states. We find a strong correlation between ZEBs and TGF-β and negative correlations between miR-200 and TGF-β and between miR-200 and ZEBs, in invasive ductal carcinomas, consistent with an autocrine TGF-β/ZEB/miR-200 signaling network being active in breast cancers.

Reversal and prevention of arsenic-induced human bronchial epithelial cell malignant transformation by microRNA-200b

Arsenic is a well-recognized human carcinogen, yet the mechanism by which it causes human cancer has not been elucidated. MicroRNAs (miRNAs) are a big family of small noncoding RNAs and negatively regulate the expression of a large number of protein-coding genes. We investigated the role of miRNAs in arsenic-induced human bronchial epithelial cell malignant transformation and tumor formation. We found that prolonged exposure of immortalized p53-knocked down human bronchial epithelial cells (p53(low)HBECs) to low levels of arsenite (NaAsO₂, 2.5 μM) caused malignant transformation that was accompanied by epithelial to mesenchymal transition (EMT) and reduction in the levels of miR-200 family members. Stably reexpressing miR-200b in arsenite-transformed cells (As-p53(low)HBECs) completely reversed their transformed phenotypes, as evidenced by inhibition of colony formation in soft agar and prevention of xenograft tumor formation in nude mice. Moreover, stably expressing miR-200b alone in parental nontransformed p53(low)HBECs was sufficient to completely prevent arsenite exposure from inducing EMT and malignant transformation. Further mechanistic studies showed that depletion of miR-200 in arsenite-transformed cells involved induction of the EMT-inducing transcription factors zinc-finger E-box-binding homeobox factor 1 (ZEB1) and ZEB2 and increased methylation of miR-200 promoters. Stably expressing ZEB1 alone in parental nontransformed p53(low)HBECs was sufficient to deplete miR-200, induce EMT and cause cell transformation, phenocopying the oncogenic effect of 16-week arsenite exposure. These findings establish for the first time a causal role for depletion of miR-200b expression in human cell malignant transformation and tumor formation resulting from arsenic exposure.

High-risk human papillomavirus in esophageal squamous cell carcinoma

BACKGROUND

Although most cases of esophageal squamous cell carcinoma (ESCC) in western populations have been attributed to high levels of exposure to tobacco and alcohol, infectious agents have been postulated as possible causes, particularly human papillomavirus (HPV).

METHODS

To explore this issue, we analyzed HPV DNA prevalence and HPV types together with lifestyle factors, in relation to tumor stage and survival in a low-incidence population. Archived tumor samples from a nationwide cohort of 222 ESCC patients were tested for the presence of HPV DNA by PCR; positive samples were sequenced to determine HPV type, and p16(INK4a) status was assessed by immunohistochemistry.

RESULTS

Of 222 ESCC patients, 8 tested HPV positive (prevalence, 3.6%; 95% confidence interval, 1.1-6.1%), of which 6 were HPV-16 positive and 2 were HPV-35 positive. Four of the eight HPV-positive tumors overexpressed p16(INK4a). None of 55 normal esophageal tissue samples from healthy participants had any detectable HPV. Although the numbers were low, it seemed that patients with HPV-positive ESCC tumors were younger than those with HPV-negative tumors (mean age, 60.8 versus 65.3 years, P = 0.18) and had higher body mass index (BMI) throughout life (mean current BMI of 25.1 for HPV positive, 22.2 for HPV negative, P = 0.08; mean BMI at 20 years of 25.8 for HPV positive, 22.1 for HPV negative, P = 0.003). We found no difference between patients with HPV-positive and HPV-negative tumors with respect to other lifestyle factors.

CONCLUSIONS

These findings suggest a very low prevalence of HPV DNA in human ESCC.

IMPACT

HPV is very unlikely to be a common cause of ESCC in Australia.

The effects of high-dose esomeprazole on gastric and oesophageal acid exposure and molecular markers in Barrett's oesophagus

BACKGROUND

Acid reflux is often difficult to control medically.

AIM

To assess the effect of 40 mg twice daily esomeprazole (high-dose) on gastric and oesophageal pH and symptoms, and biomarkers relevant to adenocarcinoma, in patients with Barrett's oesophagus (BO).

METHODS

Eighteen patients, treated with proton pump inhibitors as prescribed by their treating doctor, had their therapy increased to high-dose esomeprazole for 6 months.

RESULTS

At entry into the study, 9/18 patients had excessive 24-h oesophageal acid exposure, and gastric pH remained <4 for >16 h in 8/18. With high-dose esomeprazole, excessive acid exposure occurred in 2/18 patients, and gastric pH <4 was decreased from 38% of overall recording time and 53% of the nocturnal period to 15% and 17%, respectively (P < 0.001). There was a reduction in self-assessed symptoms of heartburn (P = 0.0005) and regurgitation (P < 0.0001), and inflammation and proliferation in the Barrett's mucosa. There was no significant change in p53, MGMT or COX-2 expression, or in aberrant DNA methylation.

CONCLUSIONS

High-dose esomeprazole achieved higher levels of gastric acid suppression and control of oesophageal acid reflux and symptoms, with significant decreases in inflammation and epithelial proliferation. There was no reversal of aberrant DNA methylation.

Methylation of CLDN6, FBN2, RBP1, RBP4, TFPI2, and TMEFF2 in esophageal squamous cell carcinoma

In the development and progression of cancer, tumor suppressor genes may be silenced by mechanisms such as methylation. Thus the discovery of new genes silenced by methylation may uncover new tumor suppressor genes, and improve our understanding of cancer biology. In this study we investigated the methylation of 19 genes in esophageal squamous cell carcinoma. Methylation was measured in 10 of these genes in esophageal squamous cell carcinoma cell lines: CDH13, CLDN6, C16orf62, FBN2, FNBP1, ID4, RBP1, RBP4, TFPI2 and TMEFF2. To determine if there was a correlation between DNA methylation and gene silencing, each cell line was cultured with or without the demethylating drug 5-aza-2'-deoxycytidine (aza-dC). For 6 genes (CLDN6, FBN2, RBP1, RBP4, TFPI2 and TMEFF2) there was an association between reduction of methylation and increase in mRNA expression in the demethylated cell lines. The frequency of the methylation of these 6 genes in esophageal squamous cell carcinoma resection specimens was also investigated. All 6 genes showed more frequent methylation in the tumor than the matched proximal resection margin of uninvolved esophagus. There was a significant difference in the frequency of methylation and in the extent of the methylation between the cancer and the margin tissues for CLDN6, FBN2, TFPI2 and TMEFF2 (P=0.0007, P=0.0048 P=0.0002 and P<0.0001, respectively). This is the first report of gene silencing by methylation of CLDN6, FBN2, RBP4, TFPI2 and TMEFF2 in esophageal squamous cell carcinoma.

Quantitation of DNA methylation by melt curve analysis

BACKGROUND

Methylation of DNA is a common mechanism for silencing genes, and aberrant methylation is increasingly being implicated in many diseases such as cancer. There is a need for robust, inexpensive methods to quantitate methylation across a region containing a number of CpGs. We describe and validate a rapid, in-tube method to quantitate DNA methylation using the melt data obtained following amplification of bisulfite modified DNA in a real-time thermocycler.

METHODS

We first describe a mathematical method to normalise the raw fluorescence data generated by heating the amplified bisulfite modified DNA. From this normalised data the temperatures at which melting begins and finishes can be calculated, which reflect the less and more methylated template molecules present respectively. Also the T50, the temperature at which half the amplicons are melted, which represents the summative methylation of all the CpGs in the template mixture, can be calculated. These parameters describe the methylation characteristics of the region amplified in the original sample.

RESULTS

For validation we used synthesized oligonucleotides and DNA from fresh cells and formalin fixed paraffin embedded tissue, each with known methylation. Using our quantitation we could distinguish between unmethylated, partially methylated and fully methylated oligonucleotides mixed in varying ratios. There was a linear relationship between T50 and the dilution of methylated into unmethylated DNA. We could quantitate the change in methylation over time in cell lines treated with the demethylating drug 5-aza-2'-deoxycytidine, and the differences in methylation associated with complete, clonal or no loss of MGMT expression in formalin fixed paraffin embedded tissues.

CONCLUSION

We have validated a rapid, simple in-tube method to quantify methylation which is robust and reproducible, utilizes easily designed primers and does not need proprietary algorithms or software. The technique does not depend on any operator manipulation or interpretation of the melt curves, and is suitable for use in any laboratory with a real-time thermocycler. The parameters derived provide an objective description and quantitation of the methylation in a specimen, and can be used to for statistical comparisons of methylation between specimens.

NS-398 induces apoptosis in human esophageal cancer cells through inhibition of NF-kappaB downstream regulation of cyclooxygenase-2

Although non-steroidal anti-inflammatory drugs (NSAIDs) have been demonstrated to have cancer-preventive effects and induce apoptosis of cancer cells, the mechanism of their effects is not clearly known. We studied the mechanism in human esophageal cancer cell line TE13. The esophageal squamous cell carcinoma cell line TE-13 was cultured with NS-398 at different concentrations or for different times. Proliferation and apoptosis were measured by MTT reduction and flow cytometry. Prostaglandin F(1alpha) was determined with radioimmunoassay. Expression of COX-2 mRNA was measured by RT-PCR and COX-2 protein levels with Western blot analysis. Nuclear NF-kappaB and cytoplasmic IkappaB protein levels were determined by electrophoretic mobility shift assay and Western blot, respectively. NS-398 significantly inhibited cell proliferation and induced apoptosis at concentrations of 0.001, 0.01, 1, and 100 micromol/L. NS-398 dose-dependently decreased the levels of COX-2 mRNA, COX-2 protein, nuclear NF-kappaB protein and production of PGF(1alpha) and increased the cytoplasmic IkappaB protein. In conclusion, NS-398 inhibits the proliferation of, and induced apoptosis in, the cultured TE-13 SCC cell line. These changes correlate with a reduction in COX-2 mRNA and protein expression, prostaglandin synthesis, an inhibition of NF-kappaB nuclear translocation, and an increase in cytoplasmic IkappaB.

Similarity of aberrant DNA methylation in Barrett's esophagus and esophageal adenocarcinoma

Background

Barrett's esophagus (BE) is the metaplastic replacement of squamous with columnar epithelium in the esophagus, as a result of reflux. It is the major risk factor for the development of esophageal adenocarcinoma (EAC). Methylation of CpG dinucleotides of normally unmethylated genes is associated with silencing of their expression, and is common in EAC. This study was designed to determine at what stage, in the progression from BE to EAC, methylation of key genes occurs.

Results

We examined nine genes (APC, CDKN2A, ID4, MGMT, RBP1, RUNX3, SFRP1, TIMP3, and TMEFF2), frequently methylated in multiple cancer types, in a panel of squamous (19 biopsies from patients without BE or EAC, 16 from patients with BE, 21 from patients with EAC), BE (40 metaplastic, seven high grade dysplastic) and 37 EAC tissues. The methylation frequency, the percentage of samples that had any extent of methylation, for each of the nine genes in the EAC (95%, 59%, 76%, 57%, 70%, 73%, 95%, 74% and 83% respectively) was significantly higher than in any of the squamous groups. The methylation frequency for each of the nine genes in the metaplastic BE (95%, 28%, 78%, 48%, 58%, 48%, 93%, 88% and 75% respectively) was significantly higher than in the squamous samples except for CDKN2A and RBP1. The methylation frequency did not differ between BE and EAC samples, except for CDKN2A and RUNX3 which were significantly higher in EAC. The methylation extent was an estimate of both the number of methylated alleles and the density of methylation on these alleles. This was significantly greater in EAC than in metaplastic BE for all genes except APC, MGMT and TIMP3. There was no significant difference in methylation extent for any gene between high grade dysplastic BE and EAC.

Conclusion

We found significant methylation in metaplastic BE, which for seven of the nine genes studied did not differ in frequency from that found in EAC. This is also the first report of gene silencing by methylation of ID4 in BE or EAC. This study suggests that metaplastic BE is a highly abnormal tissue, more similar to cancer tissue than to normal epithelium.

Genome-wide copy number analysis in esophageal adenocarcinoma using high-density single-nucleotide polymorphism arrays

We applied whole-genome single-nucleotide polymorphism arrays to define a comprehensive genetic profile of 23 esophageal adenocarcinoma (EAC) primary tumor biopsies based on loss of heterozygosity (LOH) and DNA copy number changes. Alterations were common, averaging 97 (range, 23-208) per tumor. LOH and gains averaged 33 (range, 3-83) and 31 (range, 11-73) per tumor, respectively. Copy neutral LOH events averaged 27 (range, 7-57) per EAC. We noted 126 homozygous deletions (HD) across the EAC panel (range, 0-11 in individual tumors). Frequent HDs within FHIT (17 of 23), WWOX (8 of 23), and DMD (6 of 23) suggest a role for common fragile sites or genomic instability in EAC etiology. HDs were also noted for known tumor suppressor genes (TSG), including CDKN2A, CDKN2B, SMAD4, and GALR1, and identified PDE4D and MGC48628 as potentially novel TSGs. All tumors showed LOH for most of chromosome 17p, suggesting that TSGs other than TP53 may be targeted. Frequent gains were noted around MYC (13 of 23), BCL9 (12 of 23), CTAGE1 (14 of 23), and ZNF217 (12 of 23). Thus, we have confirmed previous reports indicating frequent changes to FHIT, CDKN2A, TP53, and MYC in EAC and identified additional genes of interest. Meta-analysis of previous genome-wide EAC studies together with the data presented here highlighted consistent regions of gain on 8q, 18q, and 20q and multiple LOH regions on 4q, 5q, 17p, and 18q, suggesting that more than one gene may be targeted on each of these chromosome arms. The focal gains and deletions documented here are a step toward identifying the key genes involved in EAC development.

Methylation of TIMP3 in esophageal squamous cell carcinoma

AIM: To measure the frequency of DNA methylation of the tissue inhibitor of metalloproteinase 3 (TIMP3) promoter and relate this to any change of gene expression in esophageal squamous cell carcinoma in patients from a region of high incidence in China.

METHODS: Cancer cell lines were treated with or without the demethylating reagent 5-aza-2’-deoxycytidine. Methylation of the TIMP3 promoter was assessed in three regions by melt curve analysis and its expression was assessed by real-time RT-PCR. Tumors and proximal resection margins were obtained from 64 patients with esophageal squamous cell carcinoma from a region of high incidence in China. Methylation was assessed by melt curve analysis and expression by immunohistochemistry.

RESULTS: Methylation in one of the three promoter regions assessed correlated with gene silencing in esophageal cell lines. A degree of methylation of TIMP3 was found in only four esophageal squamous cell carcinomas, and partial loss of TIMP3 protein expression in just one.

CONCLUSION: Methylation and loss of expression of TIMP3 occurs infrequently in esophageal squamous cell carcinoma in a region of high incidence in China.

Use of ethylenediaminetetraacetic acid for in vivo stripping of columnar mucosa: pilot study in an experimental model

BACKGROUND

Barrett's oesophagus is an important clinical problem that can lead to oesophageal adenocarcinoma. A variety of mucosal ablation strategies are now being applied in an attempt to prevent this, although they all can cause complications. Animal experiments that suggest that ethylenediaminetetraacetic acid (EDTA) could be a novel agent for ablation of Barrett's oesophagus are reported in this article.

METHODS

Dark Agouti rats were used in all experiments. To determine the feasibility of using EDTA to strip intestinal type mucosa, segments of the small intestine were exposed in vitro to EDTA at various concentrations with or without agitation. The conditions required for EDTA to strip mucosa from a vascularized loop of small bowel were then optimized in vivo. Cannulated small bowel loops were irrigated with different concentrations of EDTA with or without pulsation of the irrigation solution. The effect of similar treatments on the normal mucosa of the rat oesophagus was then determined. Mucosal healing after EDTA stripping was studied in an isolated small bowel loop survival model.

RESULTS

Ethylenediaminetetraacetic acid with agitation or pulsation resulted in stripping of the intestinal columnar mucosa in vitro and in vivo. The extent was influenced by the concentration of EDTA and duration of exposure. Squamous epithelium was relatively resistant to stripping. In the survival model the small bowel mucosa regenerated without stricture formation.

CONCLUSION

Small bowel columnar mucosa can be removed by EDTA in vivo without stricture formation. A refinement of this approach could be applicable to the ablation of Barrett's oesophagus.

Aspirin induces apoptosis in oesophageal cancer cells by inhibiting the pathway of NF-kappaB downstream regulation of cyclooxygenase-2

BACKGROUND

Aspirin has potential in the prevention or treatment of oesophageal cancer, the seventh most common cancer in the world, but its mechanism of action is still not certain.

METHODS

The oesophageal squamous cell carcinoma cell line TE-13 was cultured with aspirin at different concentrations or for different times. Proliferation and apoptosis were measured by MTT reduction and flow cytometry. Expression of COX-2 mRNA was measured by RT-PCR and COX-2 protein levels with Western blot analysis. Nuclear NF-kappaB and cytoplasmic IkappaB protein levels were determined by electrophoretic mobility shift assay and Western blot, respectively.

RESULTS

Aspirin significantly inhibited cell proliferation and induced apoptosis at concentrations of 1, 4, 8 mmol/L. Aspirin dose-dependently decreased the levels of COX-2 mRNA, COX-2 protein and nuclear NF-kappaB protein and increased the cytoplasmic IkappaB protein.

CONCLUSION

We conclude that aspirin inhibits the proliferation of, and induced apoptosis in, the cultured TE-13 SCC cell line. These changes correlate with a reduction in COX-2 mRNA and protein expression, prostaglandin synthesis, an inhibition of NF-kappaB nuclear translocation, and an increase in cytoplasmic IkappaB. These results support the further investigation of the cyclooxygenase pathway in investigating the potential of aspirin and similar drugs in cancer prevention and therapy.

Metallothionien 3 expression is frequently down-regulated in oesophageal squamous cell carcinoma by DNA methylation

Background

Metallothionein 3 (MT3) inhibits growth in a variety of cell types. We measured MT3 gene expression by RT-PCR, and DNA methylation in the MT3 promoter by combined bisulphite restriction analysis, in four oesophageal cancer cell lines and the resected oesophagus from 64 patients with oesophageal squamous cell carcinoma (SCC).

Results

MT3 expression was not detected in one of the four oesophageal cell lines. The MT3 promoter was methylated in all of the oesophageal cell lines, but the degree of methylation was greater in the non-expressing cell line. After treatment with 5-aza-2'-deoxycytidine there was a reduction in the degree of methylation, and an increase in MT3 expression, in each of the cell lines (p < 0.01). Methylation was detected in 52% (33 of 64) of primary SCC and 3% (2 of 62) of histologically normal resection margins. MT3 expression was measured in 29 tumours, 17 of which had methylation of MT3. The expression of MT3 was significantly less in the methylated tumours compared to either the unmethylated tumours (p = 0.03), or the matched margin (p = 0.0005). There was not a significant difference in MT3 expression between the tumour and the margin from patients with unmethylated tumour. No correlations were observed between methylation of MT3 and survival time, patient age, gender, smoking or drinking history, tumour stage, volume, or lymph node involvement.

Conclusion

We conclude that MT3 expression is frequently down-regulated in oesophageal SCC, by DNA methylation, but that this is not a prognostic indicator.

Cyclo-oxygenase-2 expression in esophageal adenocarcinoma as a determinant of clinical outcome following esophagectomy

The aim of this study was to determine if cyclo-oxygenase-2 (COX-2) expression in adenocarcinoma of the esophagus affects survival outcome in patients undergoing esophagectomy. Ten patients surviving more than 3 years following an esophagectomy for adenocarcinoma of the esophagus were identified from an esophagectomy database maintained by the University of Adelaide Department of Surgery. An additional group of 10 patients, who underwent esophagectomy for adenocarcinoma, but who died within 12 months of surgery due to recurrent disease, were also identified. Pieces of the original formalin fixed carcinoma tissue embedded in paraffin blocks from all of these patients were obtained, and slices of the tumor specimens underwent immunohistochemical staining with COX-2 protein. The extent of staining was then graded by a single 'blinded' pathologist: grade 0, no staining; grade 1 +, limited staining; and grade 2 +, strong staining. Kaplan-Meier survival curves were then constructed and used to determine correlations between survival and COX-2 staining, tumor T-stage, local lymph node metastases, and tumor vascular invasion. Ninety-five percent (19/20) of patients stained positively for COX-2. Patients with grade 2 + staining had a significantly poorer survival outcome compared to grade 1 + patients (P = 0.03). There were also trends towards shorter survival with worsening T-stage, lymph node metastasis and vascular invasion. COX-2 protein appears to be expressed by most esophageal adenocarcinomas. An increased level of expression of COX-2 was associated with a poorer survival outcome in this study. COX-2 protein expression association could be a better prognostic indicator for esophageal adenocarcinoma than traditional histopathological staging.

Aspirin and indomethacin for the prevention of experimental port-site metastases

BACKGROUND

Nonsteroidal antiinflammatory drugs have been shown to have antitumor and chemopreventative effects. We investigated the potential of these drugs to inhibit port-site and intraperitoneal metastases.

METHODS

The antiproliferative effect of aspirin and indomethacin on tumor cells was measured in vitro and in vivo. The in vivo experiments used DA rats to measure the effects of aspirin and indomethacin on the development of port-site metastases and the proliferation of intraperitoneal tumor cells after laparoscopy.

RESULTS

In vitro, aspirin and indomethacin had an antiproliferative effect on tumor cells, inhibiting cell division and killing cells in a concentration and time-dependent manner. Orally administered aspirin and indomethacin, at the maximum tolerated dose, did not reduce the rate of intraperitoneal tumor cell division and had no effect on peritoneal metastases, or the number or size of port-site metastases.

CONCLUSIONS

Despite promising in vitro studies, this study does not suggest there will be any clinical therapeutic value associated the use of aspirin or indomethacin for the prevention of the spread of tumor following the spillage of cells into the peritoneal cavity at laparoscopic surgery.

DECREASED PHAGOCYTIC CAPACITY OF AUTOTRANSPLANTED SPLENIC TISSUE

BACKGROUND

Asplenic patients have an increased risk of infections. Operations such as autotransplantation have been proposed to restore functional splenic tissue after splenectomy, but the protective value of this tissue is unclear. Immune responses such as production of antibody remain impaired in humans and animals even when such tissue is present, and clearance of particles from the blood is reported to be less efficient than by normal spleen tissue. The present study investigated the phagocytic capacity of cells in the regenerated tissue in vitro, free of the confounding effects of hepatic clearance.

METHODS

Single cell suspensions were prepared from splenic tissue from rats 6 months after splenic autotransplantation or sham operation. Phagocytosis of killed, fluorescein-labelled bacteria was measured by flow cytometry.

RESULTS

Autotransplanted tissue contained fewer phagocytic cells than normal tissue, and these cells phagocytosed less per cell. Phagocytosis by spleen cells was dependent on heat-labile opsonic factors.

CONCLUSIONS

Autotransplanted splenic tissue does not restore the phagocytic capacity lost following splenectomy.

Benign cellular changes in Pap smears. Causes and significance

OBJECTIVE

We reviewed consecutive cases classified as benign cellular changes (BCC) over a four-month period.

STUDY DESIGN

Cases classified as BCC were retrieved from the cytology files. A search was carried out to identify the previous Pap smears and concomitant cervical biopsies.

RESULTS

One thousand one hundred three cases (23% of our gynecologic smears) were classified as BCC. Ninety-two patients (8.3%) underwent concurrent cervical biopsies. Specific infections accounted for 8% of BCC cases; reactive changes accounted for 92%. Of the biopsy specimens, 8.3% had no significant pathologic change. The most common biopsy diagnoses were cervicitis (31.5%), immature squamous metaplasia (16.3%) and reserve cell hyperplasia (10.8%). Miscellaneous benign diagnoses accounted for 21.7%. Cervical intraepithelial neoplasia (CIN) 1/human papillomavirus (HPV) was present in 14% of cases. All patients with biopsy diagnoses of CIN 1 had at least two previous abnormal Pap smears. Previous biopsy reports were available for review in 127 (12%) of the 1,103 patients. Of these 127 cases, 53.5% had a previous diagnosis of CIN/HPV; 9.4% had invasive carcinoma. A benign diagnosis was reported in 36.5%.

CONCLUSION

The majority of BCC cases are due to reactive and inflammatory processes. In patients with a previous history of CIN, BCC may be of some significance. In patients with no significant prior cervical abnormalities, a Pap smear classified as BCC represents a reactive process.

Immune cell subpopulations in regenerated splenic tissue in rats

BACKGROUND

Asplenic patients have an increased risk of infections. Operations such as autotransplantation or splenic artery ligation have been suggested to ensure retention of functional splenic tissue after splenectomy, but their protective value is unclear. Immune responses, such as production of antibody, remain impaired in humans and animals even when such tissue is present, and phagocytosis is less efficient than by normal spleen tissue. In the present study the cellular composition of regenerated tissue is determined.

METHODS

Splenic tissue was obtained from rats 6-9 months after splenic autotransplantation, splenic artery ligation or sham operation. The lymphocyte and macrophage subpopulations were labelled using a panel of monoclonal antibodies and analysed by flow cytometry.

RESULTS

Both the total number of cells and the number of cells per gram of tissue were significantly reduced. There was a substantial reduction in the percentage of some of the cells examined (CD4+ and CD8+ T lymphocytes subsets), but not all (B lymphocytes, ED1+ and ED2+ macrophages, OX2+ and OX6+ cells).

CONCLUSIONS

The reduction in the T lymphocyte subsets in regenerated splenic tissue compared with the normal spleen might explain the immunological dysfunction which persists after splenic autotransplantation. The reduction in the number of macrophages may be responsible for the alteration in phagocytic efficiency of regenerated splenic tissue.

Do qualifiers of ASCUS distinguish between low- and high-risk patients?

OBJECTIVE

To evaluate the qualification of a Pap smear classified as atypical squamous cells of undetermined significance (ASCUS) favor reactive or neoplasia as recommended by the Bethesda System.

STUDY DESIGN

The smears from 105 concurrent patients with a cytologic diagnosis of ASCUS not otherwise qualified were reviewed and subclassified as ASCUS favor reactive, low grade squamous intraepithelial lesion (LSIL) or high grade squamous intraepithelial lesion (HSIL) based on the Bethesda System criteria. The cervical biopsy diagnoses were correlated.

RESULTS

Of the 105 cases classified as ASCUS, 37 were subclassified as favor reactive, 51 as favor LSIL and 17 as favor HSIL on cytologic review. In the ASCUS favor reactive group, 19 (51%) had reactive changes on biopsy, 17 (46%) had cervical intraepithelial neoplasia (CIN) 1, and 1 (2%) had CIN 3. A total of 48% patients had CIN. In the favor LSIL group, there was CIN 1 in 28 cases (55%), CIN 2 or 3 in 12 (23%) and benign changes in 11 (22%) on biopsy. Seventy-eight percent had CIN. In the 17 cases classified as ASCUS favor HSIL group, all had CIN.

CONCLUSION

Of the total 105 cases of ASCUS, 71% had CIN, 29% had reactive changes on follow-up biopsies, and 48% of patients in the ASCUS favor reactive group had CIN. Qualifiers of ASCUS have questionable utility in patient management.

Prostatectomy tissue for research: balancing patient care and discovery

The application of modern technology in basic research often requires fresh tissue from human organs. The acquisition of this tissue challenges the anatomic pathologist to balance the needs of the basic scientist with the requirements of quality patient care. Our experience indicates that fresh tissue adequate for research can be obtained from neoplastic prostate glands without compromising patient care. The process requires dedicated, knowledgeable individuals and extensive documentation. Potential problems include low yield for research studies, loss of all residual carcinoma, compromise of the specimen margin, and unforeseen costs. Best collaborations occur in situations in which basic scientists and anatomic pathologists establish a working relationship and develop a mutually supportive means of funding.

Pulmonary cryptococcosis and pituitary Cushing's disease

Pulmonary cryptococcosis was diagnosed by examining smears obtained by fine-needle aspiration (FNA) in a patient with pituitary Cushing's disease. FNA allowed for rapid diagnosis and prompt treatment of a potentially serious infection. The patient fully recovered from her pulmonary disease. Although opportunistic infections may occur in patients with endogenous Cushing's syndrome, it is rare to see such infections in the subset of patients with pituitary Cushing's disease. Hypercortisolism associated with Cushing's syndrome appears to induce a transitory immune deficiency state and opens a window of opportunity for certain infectious agents such as Cryptococcus neoformans to exploit. To our knowledge, this is the third such case reported in this clinical setting, and the first diagnosed by FNA.

Fat distribution and changes in the blood brain barrier in a rat model of cerebral arterial fat embolism

This study was designed to determine the distribution of fat which reaches the brain by the internal carotid artery, and the consequent alterations in the blood brain barrier, in a rat model of cerebral arterial fat embolism. The distribution of the blood flow in this model was determined by the injection of radiolabelled microspheres. Over 44% were trapped in the brain, 43% in the extracerebral tissues of the head and neck, and 7% in the lungs. Over 30% of radiolabelled triolein was present within the brain 30 min after injection, and 4% still remained after 17 days. Approximately 25% of the triolein which went to the brain moved through the cerebral vessels and left within the first 15 min. The majority of the triolein distributed to the ipsilateral cerebral hemisphere, with significantly less to the contralateral cerebral hemisphere, brain stem and cerebellum. The blood brain barrier opened, as measured by uptake of 99mTc, within the first 15 min and remained open for at least 3 days. A significant percentage of fat reaching the brain persists for days, and causes rapid and long-lasting damage to the blood brain barrier.

Can androgen deprivation with leuprolide be predicted from histology alone? If not, why not?

PURPOSE

Androgen deprivation therapy with analogues of luteinizing hormone-releasing hormone produces distinctive histological changes in neoplastic and nonneoplastic prostate tissue. Others have described these features in cases in which treatment status was known. To our knowledge the specificity and sensitivity of luteinizing hormone-releasing hormone effects based only on histology and possible reasons for interobserver variation have not been addressed previously.

MATERIALS AND METHODS

Slides from 97 prostatectomies performed in a 3-year period were reviewed by 2 observers blinded to knowledge of previous hormonal treatment. The observers evaluated each case, recording the presence or absence of 14 features associated with androgen deprivation therapy, and then made an overall assessment regarding treatment status.

RESULTS

Of the 97 patients 31 had received androgen deprivation therapy with the luteinizing hormone-releasing hormone agonist leuprolide. A luteinizing hormone-releasing hormone effect was identified by the 2 observers in 26 and 28, respectively, of the 31 cases (83.9 versus 90.3% sensitivity and 92.4 versus 80.3% specificity). Including focal changes as consistent with androgen deprivation therapy increased sensitivity but decreased specificity. Of the 14 features 12 had a significant association for predicting treatment status.

CONCLUSIONS

Interobserver variations in interpretation occurred although both examiners were experienced in the evaluation of luteinizing hormone-releasing hormone effects and they used exactly the same criteria. These variations were apparently due to differences in the value (mental weight) given by each observer to the features assessed in each case. Predicting treatment status was optimized by noting a luteinizing hormone-releasing hormone effect only when changes were diffuse, improving specificity significantly with only a modest decrease in sensitivity.

The nested variant of transitional cell carcinoma: an aggressive neoplasm with innocuous histology

The nested variant of transitional cell carcinoma (TCC-NV) is a rare neoplasm; only eight cases have been described. This report reviews the clinicopathologic features of 16 additional examples. The cases were collected from consultations received during a 13-year period. In most instances, a consultation was sought because the histologic features suggested an atypical proliferation of Brunn's nests or a lesion similar to the previously published examples of TCC-NV. Clinical data were gathered and tissues were studied to exclude prostatic cancer and adenocarcinoma. TCC-NV is characterized by the presence of irregular nests and/or tubules of transitional cells infiltrating the lamina propria without surface involvement. Neoplastic cells tend to have innocuous features but at least a few cells in every case are cytologically anaplastic. There is a marked male predominance. Synchronous or metachronous TCCs of more usual histologic make-up may occur. After a follow-up averaging 16.6 months, only three patients are known to be alive with no evidence of disease. Clinicopathologic information from our 16 cases combined with the 8 previously reported examples confirms that TCC-NV is a persistent and aggressive neoplasm notable for its innocuous appearance in histologic preparations.

Prognostic factors in carcinoma of the vulva: a clinicopathologic and DNA flow cytometric study

The clinical staging of carcinoma of the vulva is a predictor of patient survival; however, the significance of other prognostic factors remains somewhat controversial. Length of survival after diagnosis of invasive squamous cell carcinoma was determined for 39 clinically staged and surgically treated patients who were followed at our institution. Clinical stage, tumor type, use of radiotherapy (RT), histopathologic features (invasive pattern, depth of invasion, lymph node status, nuclear grade, adjacent dysplasia, desmoplasia, inflammation) and DNA ploidy (determined by flow cytometry from paraffin-embedded tissue) were evaluated as predictors of survival. Kaplan-Meier survival curves were generated for strata defined by each of the various predictors and compared using the log-rank test. Advanced stage (p = 0.0002), RT use (p = 0.0004), "spray" invasive pattern (p = 0.005), positive lymph node status (p = 0.001), increased positive lymph node number (p = 0.016), and greater depth of invasion (p = 0.039) were associated univariantly with decreased survival time. Spray invasive pattern (p = 0.018), positive lymph node status (p = 0.030), positive lymph node number (p = 0.040), and RT use (p = 0.045) continued to be associated with decreased survival time after controlling for stage. Of the significant factors, invasive pattern stands out as a qualitative feature that may have potential benefit in predicting survival independent of clinical stage in patients with vulvar carcinoma.

The histogenesis of clear cell adenocarcinoma of the lower urinary tract. Case series and review of the literature

Clear cell adenocarcinoma of the lower urinary tract is a rare neoplasm whose histogenesis has not been thoroughly investigated. We have examined six specimens of clear cell adenocarcinomas collected from three institutions using histological, histochemical, and immunohistochemical techniques. Results indicate that almost all clear cell adenocarcinomas of this region express morphological and antigenic features, suggesting müllerian differentiation, and that müllerian differentiation is not a feature of either nonclear cell adenocarcinomas or normal female paraurethral glands. Including the authors' six specimens, 46 specimens have been reported in the available English literature. The accumulated experience confirms the initial impression that these tumors develop predominantly in the urethras of women and occur over a wide age range. Despite high stage at diagnosis, most patients have been alive with no evidence of disease when reported, a prognosis that seems to apply regardless of length of follow-up.

Cerebral arterial fat embolism in the rabbit

This study was designed to measure the effects of cerebral arterial fat embolism on cerebral blood flow and function. Rabbits were injected via the left internal carotid artery with the neutral triglyceride triolein. Left cerebral blood flow was measured by laser Doppler flowmetry, and left sided brain function by electrocorticogram and cortical somatosensory evoked responses following electrical stimulation of the forepaw. Readings were taken for 2 h before injection to establish a baseline, and for 3 h after injection. Cerebral blood flow was significantly decreased at 45 min after the injection of the lipid, then progressively decreased further to approximately 50% of baseline after 2 h, at which level it remained for the last hour of the experiment. The electrocorticogram was rapidly, but transiently, suppressed. The evoked responses did not differ from baseline at each of the time points measured. Using 125I-triolein, 2.49% of the injected dose was measured in the brain 3 min after injection. The results show that in this rabbit model of cerebral arterial fat embolism only a small percentage of injected lipid passes into the brain, but this is sufficient to cause a reduction in cerebral blood flow over the following 2 h. The evoked responses never alter significantly from baseline values.

Pathology of androgen deprivation therapy in prostate carcinoma. A comparative study of 173 patients

BACKGROUND

Leuprolide, an agonist of luteinizing hormone-releasing hormone (LH-RH), and flutamide, an antiandrogen, increasingly are being used in the treatment of clinically localized prostate cancer. Only two small series (of 23 and 12 patients) have been published on the distinctive pathologic changes induced in the prostate by androgen deprivation therapy with discrepancies on the presence of squamous metaplasia, necrosis, and possible tumor destruction by combined androgen deprivation therapy.

METHODS

One hundred and thirteen radical prostatectomy specimens obtained after at least 3 months of leuprolide-flutamide androgen inhibition therapy and 60 nonhormonally treated prostates in randomly selected clinical Stage T2 prostate adenocarcinoma patients were entirely sectioned. Distinctive histologic findings were tabulated and their statistical value determined.

RESULTS

Resection margins of excision were involved by tumor in 43% of untreated and in 19% of androgen-deprived patients. Characteristic changes in androgen-inhibited nontumor glands included atrophy, basal cell prominence, vacuolated luminal cell layer, and squamous and transitional cell metaplasia. Prostatic intraepithelial neoplasia (PIN) was observed in 35% of treated patients. The presence of small tumor glands separated by stroma was the most frequently noted effect of androgen deprivation on prostate adenocarcinoma; pyknosis and branching empty spaces were less frequent. Large clear tumor cells within an inflammatory response was a third histologic pattern. Apparently unaltered tumor areas were observed in 43% of prostates exposed to androgen deprivation therapy.

CONCLUSIONS

Androgen deprivation therapy results in histologically distinctive changes that can be recognized in both nonneoplastic and neoplastic prostate tissue. Residual tumor was present in all 113 treated radical prostatectomy specimens. In addition to glandular shrinkage, therapy was associated with statistically significant reductions in the frequency of high grade PIN and extension of cancer to prostate specimen margins of excisions.

IgG-mediated phagocytosis in regenerated splenic tissue

The risk of severe infections after splenectomy is well established. Operations such as auto-transplantation, splenic artery ligation or partial resection have been advocated for the retention or regeneration of splenic tissue following splenic trauma. The potential of such tissue to protect from infection is unclear. The ability of splenic tissue to phagocytose IgG opsonized syngeneic erythrocytes was measured in rats 6 months following splenectomy and splenic autotransplantation, splenic artery ligation, total or partial splenectomy, and compared with eusplenic controls. In eusplenic and partially splenectomized rats 71% of the label was cleared at 3 h, compared with approximately 50% in rats following total splenectomy, splenectomy and splenic autotransplantation or splenic artery ligation. The autotransplanted and the ligated splenic tissue cleared less than 10% compared with control spleen, but there was no difference between them when clearance was expressed as uptake per gram of tissue. Splenic autotransplants and ligated spleens were small and histologically abnormal, with an increase in the red pulp, significantly less white pulp and marginal zone, and the frequent absence of a central arteriole in the white pulp. The clearance of label was proportional to the amount of red pulp in the tissue, although the red pulp from the regenerated tissues was not as efficient at phagocytosis as control red pulp. The tissue which regenerated following autotransplantation or splenic artery ligation did not result in greater clearance of erythrocytes from the circulation than that which occurred in splenectomized rats.

Antibody responses following splenectomy: implications for the timing of prophylactic vaccination

Antibody responses are reduced both in the short- and long-term after splenectomy. It is not known if this reduction is more profound in the immediate postoperative period compared to later, and consequently, whether there would be an advantage in delaying prophylactic vaccination to ensure a greater antibody response. To investigate this, the effect of splenectomy on the primary and secondary antibody response to sheep red blood cells (SRBC) injected into the peritoneum (IP) of adult male Porton rats was measured after either splenectomy (Spx), sham splenectomy (Sham), anaesthesia only (Ans) or no procedure at all (Con). There was no difference in the titres of antibody between the Con and the Ans rats. There was no difference in the titres of antibody between the Sham and Spx rats, but both had significantly lower titres than the Con rats. In a separate experiment, rats were immunized 1 month or 1 year after splenectomy or sham-splenectomy. One month after the operation the antibody response of the Sham rats had increased and did not differ from that of Con rats, but in rats which had been splenectomized there was a long-term suppression of the antibody response, which did not improve for at least one year. The results suggest that, in patients requiring splenectomy for trauma and not able to be vaccinated before operation, there may be no advantage in delaying prophylactic vaccination postoperatively.

Effects of nitrite use on lymphocyte mitogenesis in homosexual men

Immune function in 97 homosexually active men (none of whom had HIV infection) was assessed. Data revealed that mitogenesis in those who used volatile nitrites compared to those who did not was higher at 72 h but that there was no difference between the groups at 96 h. In those who had high as compared to low nitrite use, mitogenesis was higher at 72 h but decreased significantly by 96 h. These data support previous suggestions that immunosuppressive effects of nitrites alone cannot account for the development of Kaposi's sarcoma in homosexual men with HIV infection.

Regeneration and phagocytic function of devascularized spleens

The phagocytic function of normal splenic tissue and of regenerated tissue following splenic artery ligation was investigated in rats using radiolabelled stannous fluoride colloid. Colloidal carbon was used to determine the histological location of phagocytosis within the spleen. Six months after ligation, the median weight of the devascularized spleens was 25% of that of spleens in control rats. Technetium stannous colloid clearance by devascularized spleens was reduced to 10% of normal and 25% when corrected for spleen weight. The colloidal carbon injected intravenously was observed primarily in the marginal zone in both normal and devascularized spleens. Histologically, devascularized spleens contained significantly less white pulp and marginal zone. The splenic tissue which regenerates following ligation does not have the phagocytic ability of normal splenic tissue. This may be due to the decreased regrowth of the lymphoid compartments of the spleen.

Scanning electron microscopy of dysplastic Barrett's epithelium

Twenty-six patients with Barrett's esophagus (BE) were followed prospectively by endoscopic examination and biopsy. Two biopsies were taken from each of 4 areas of BE. One was processed for light microscopy (LM) and one for scanning electron microscopy (SEM). Those in whom dysplastic BE was demonstrated by LM were reexamined at 6-mo intervals, and the others at yearly intervals. One patient had low grade dysplasia (LGD) by LM on entry, and in 2 others, LGD was recognized on the second examination. These changes have persisted in semiannual examinations over 3, 2, and 2 yr, respectively. SEM prints were examined without knowledge of LM findings, and features that might correlate with LGD by LM were sought. SEM findings were similar to those of Zwas et al. (Gastroenterology 90:1932, 1986) in that most glandular cells had surface features unlike either gastric or intestinal cells but unique to BE. In the patient with LGD on entry, there was an aggregate of very large cells covered by short microvilli with bald patches. In the other patients with LGD, there was more variation in size and shape of cells than in nondysplastic cases.