Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1-3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

Sequencing of prostate cancers identifies new cancer genes, routes of progression and drug targets

Prostate cancer represents a substantial clinical challenge because it is difficult to predict outcome and advanced disease is often fatal. We sequenced the whole genomes of 112 primary and metastatic prostate cancer samples. From joint analysis of these cancers with those from previous studies (930 cancers in total), we found evidence for 22 previously unidentified putative driver genes harboring coding mutations, as well as evidence for NEAT1 and FOXA1 acting as drivers through noncoding mutations. Through the temporal dissection of aberrations, we identified driver mutations specifically associated with steps in the progression of prostate cancer, establishing, for example, loss of CHD1 and BRCA2 as early events in cancer development of ETS fusion-negative cancers. Computational chemogenomic (canSAR) analysis of prostate cancer mutations identified 11 targets of approved drugs, 7 targets of investigational drugs, and 62 targets of compounds that may be active and should be considered candidates for future clinical trials.

Appraising the relevance of DNA copy number loss and gain in prostate cancer using whole genome DNA sequence data

A variety of models have been proposed to explain regions of recurrent somatic copy number alteration (SCNA) in human cancer. Our study employs Whole Genome DNA Sequence (WGS) data from tumor samples (n = 103) to comprehensively assess the role of the Knudson two hit genetic model in SCNA generation in prostate cancer. 64 recurrent regions of loss and gain were detected, of which 28 were novel, including regions of loss with more than 15% frequency at Chr4p15.2-p15.1 (15.53%), Chr6q27 (16.50%) and Chr18q12.3 (17.48%). Comprehensive mutation screens of genes, lincRNA encoding sequences, control regions and conserved domains within SCNAs demonstrated that a two-hit genetic model was supported in only a minor proportion of recurrent SCNA losses examined (15/40). We found that recurrent breakpoints and regions of inversion often occur within Knudson model SCNAs, leading to the identification of ZNF292 as a target gene for the deletion at 6q14.3-q15 and NKX3.1 as a two-hit target at 8p21.3-p21.2. The importance of alterations of lincRNA sequences was illustrated by the identification of a novel mutational hotspot at the KCCAT42, FENDRR, CAT1886 and STCAT2 loci at the 16q23.1-q24.3 loss. Our data confirm that the burden of SCNAs is predictive of biochemical recurrence, define nine individual regions that are associated with relapse, and highlight the possible importance of ion channel and G-protein coupled-receptor (GPCR) pathways in cancer development. We concluded that a two-hit genetic model accounts for about one third of SCNA indicating that mechanisms, such haploinsufficiency and epigenetic inactivation, account for the remaining SCNA losses.

The PROFILE Feasibility Study: Targeted Screening of Men With a Family History of Prostate Cancer

BACKGROUND

A better assessment of individualized prostate cancer (PrCa) risk is needed to improve screening. The use of the prostate-specific antigen (PSA) level for screening in the general population has limitations and is not currently advocated. Approximately 100 common single nucleotide polymorphisms (SNPs) have been identified that are associated with the risk of developing PrCa. The PROFILE pilot study explored the feasibility of using SNP profiling in men with a family history (FH) of PrCa to investigate the probability of detecting PrCa at prostate biopsy (PB). The primary aim of this pilot study was to determine the safety and feasibility of PrCa screening using transrectal ultrasound-guided PB with or without diffusion-weighted magnetic resonance imaging (DW-MRI) in men with a FH. A secondary aim was to evaluate the potential use of SNP profiling as a screening tool in this population.

PATIENTS AND METHODS

A total of 100 men aged 40-69 years with a FH of PrCa underwent PB, regardless of their baseline PSA level. Polygenic risk scores (PRSs) were calculated for each participant using 71 common PrCa susceptibility alleles. We treated the disease outcome at PB as the outcome variable and evaluated its associations with the PRS, PSA level, and DW-MRI findings using univariate logistic regression.

RESULTS

Of the 100 men, 25 were diagnosed with PrCa, of whom 12 (48%) had clinically significant disease. Four adverse events occurred and no deaths. The PSA level and age at study entry were associated with PrCa at PB (p = .00037 and p = .00004, respectively).

CONCLUSION

The results of the present pilot study have demonstrated that PB is a feasible and safe method of PrCa screening in men with a FH, with a high proportion of PrCa identified requiring radical treatment. It is feasible to collect data on PrCa-risk SNPs to evaluate their combined effect as a potential screening tool. A larger prospective study powered to detect statistical associations is in progress.

IMPLICATIONS FOR PRACTICE

Prostate biopsy is a feasible and safe approach to prostate cancer screening in men with a family history and detects a high proportion of prostate cancer that needs radical treatment. Calculating a polygenic risk score using prostate cancer risk single nucleotide polymorphisms could be a potential future screening tool for prostate cancer.

Multivariate modelling of prostate cancer combining magnetic resonance derived T2, diffusion, dynamic contrast-enhanced and spectroscopic parameters

OBJECTIVES

The objectives are determine the optimal combination of MR parameters for discriminating tumour within the prostate using linear discriminant analysis (LDA) and to compare model accuracy with that of an experienced radiologist.

METHODS

Multiparameter MRIs in 24 patients before prostatectomy were acquired. Tumour outlines from whole-mount histology, T2-defined peripheral zone (PZ), and central gland (CG) were superimposed onto slice-matched parametric maps. T2, Apparent Diffusion Coefficient, initial area under the gadolinium curve, vascular parameters (K(trans),Kep,Ve), and (choline+polyamines+creatine)/citrate were compared between tumour and non-tumour tissues. Receiver operating characteristic (ROC) curves determined sensitivity and specificity at spectroscopic voxel resolution and per lesion, and LDA determined the optimal multiparametric model for identifying tumours. Accuracy was compared with an expert observer.

RESULTS

Tumours were significantly different from PZ and CG for all parameters (all p < 0.001). Area under the ROC curve for discriminating tumour from non-tumour was significantly greater (p < 0.001) for the multiparametric model than for individual parameters; at 90 % specificity, sensitivity was 41 % (MRSI voxel resolution) and 59 % per lesion. At this specificity, an expert observer achieved 28 % and 49 % sensitivity, respectively.

CONCLUSION

The model was more accurate when parameters from all techniques were included and performed better than an expert observer evaluating these data.

KEY POINTS

• The combined model increases diagnostic accuracy in prostate cancer compared with individual parameters • The optimal combined model includes parameters from diffusion, spectroscopy, perfusion, and anatominal MRI • The computed model improves tumour detection compared to an expert viewing parametric maps.

Analysis of the genetic phylogeny of multifocal prostate cancer identifies multiple independent clonal expansions in neoplastic and morphologically normal prostate tissue

Genome-wide DNA sequencing was used to decrypt the phylogeny of multiple samples from distinct areas of cancer and morphologically normal tissue taken from the prostates of three men. Mutations were present at high levels in morphologically normal tissue distant from the cancer, reflecting clonal expansions, and the underlying mutational processes at work in morphologically normal tissue were also at work in cancer. Our observations demonstrate the existence of ongoing abnormal mutational processes, consistent with field effects, underlying carcinogenesis. This mechanism gives rise to extensive branching evolution and cancer clone mixing, as exemplified by the coexistence of multiple cancer lineages harboring distinct ERG fusions within a single cancer nodule. Subsets of mutations were shared either by morphologically normal and malignant tissues or between different ERG lineages, indicating earlier or separate clonal cell expansions. Our observations inform on the origin of multifocal disease and have implications for prostate cancer therapy in individual cases.

Chronic uveitis in Gaucher's disease

Thirty patients with Gaucher's disease have been examined in the authors' clinic; 29 of them suffered from the adult form and one had the juvenile type of the disease. The authors found intraocular abnormalities in four patients: three suffered from uveitis and in one, multiple vitreous opacities were observed. Two of the three patients had bilateral uveitis, while in one the uveitis was confined to the right eye only. In two of the three patients the manifestations of Gaucher's disease were present before the onset of uveitis. In one of the three, however, bilateral uveitis with spontaneous hyphema in the left eye was the presenting symptom. The diagnosis of Gaucher's disease in this case was arrived at during the work-up investigations for the etiology of the ocular manifestations. Initially the ocular symptoms in these three patients manifested as acute anterior uveitis, becoming chronic and involving also the posterior segments at a later stage.

Trends in pathologic outcomes after introduction of active surveillance in the UK: implication for focal therapy

BACKGROUND

We aimed to evaluate the trends in pathologic outcomes of clinically localized prostate cancer treated with radical prostatectomy prior to and after national guidelines placing active surveillance as the primary management in men with low-risk prostate cancer. Further, we examined whether there was a coincident change in the proportion of men potentially suitable for focal therapy.

METHODS

All cancer foci in 195 whole mount radical prostatectomy samples during two periods (Period 1: 07/2001-10/2003, n = 100 and Period 2: 01/2007-11/2009, n = 95) were examined. Individual tumor volumes, Gleason grade, and extracapsular extension/positive surgical margins were evaluated. The index lesion was defined as the largest by volume.

RESULTS

There was a statistically significant increase in the proportion of Gleason score ≥7 tumors (31-69%; P < 0.001) and pathologically non-organ confined disease (21-37%; P = 0.008), between period 1 and 2, respectively. The proportion of patients with unifocal prostate cancer potentially suitable for focal ablation was stable (14-13.7%; P = 0.9). Although there was a decrease in the proportion of patients potentially suitable for index lesion ablation (51-43%; P = 0.4) and unilateral prostate cancer potentially suitable for hemi-ablation (11-6.3%; P = 0.3), these differences were not statistically significant.

CONCLUSION

The increasing use of active surveillance in the UK may be responsible for a trend towards higher grade and stage prostate cancer in whole mount specimens. Despite this, there remain a significant proportion of men who currently undergo radical surgery who may be suitable for focal therapy, if that included index lesion ablation.

Histological characteristics of the index lesion in whole-mount radical prostatectomy specimens: implications for focal therapy

It has been suggested that in multifocal prostate cancer (PCa), focal therapy to the largest (index) lesion is sufficient, because secondary non-index lesions are unlikely to contribute to disease progression. In this study, the role of PCa focality in selecting men for focal therapy was evaluated. A histopathological analysis of the index and non-index lesions of 100 consecutive radical prostatectomy specimens was carried out. Cases that would have been suitable for focal ablation were also evaluated. Tumours were more often multifocal (78%) and bilateral (86%). In total, 270 tumour foci were identified. In multifocal disease, tumour volume, Gleason score and pathological stage were almost invariably defined by the index lesion of the specimen; among the 170 satellite foci, 148 (87%) were <0.5 cm(3) and 169 (99.4%) had Gleason score ≤ 6. Using the defined criteria, 51% of men in this series would have been considered suitable for focal ablation of the index lesion. Histological features of poor prognosis in the prostate are associated with the index lesion. There is a high proportion of patients who may be suitable for focal therapy, and clinical trials of index lesion ablation should be considered as part of this therapeutic strategy.

The role of embolization in the management of tumour recurrence after radical nephrectomy

This article presents the case of a 56-year-old woman who developed a tumour recurrence following radical nephrectomy. This was invading the descending colon and causing severe gastrointestinal haemorrhage. Angiography revealed neovascularization from T11 and T12 intercostal arteries, which were successfully embolized percutaneously.

Characteristics of incidental prostatic adenocarcinoma in contemporary radical cystoprostatectomy specimens

OBJECTIVES

To investigate the relationship between prostate-specific antigen (PSA) level and tumour volume for incidental adenocarcinoma of the prostate found in cystoprostatectomy (CP) specimens, and to analyse the incidence of clinically significant prostate cancers in CP specimens and the biochemical recurrence of incidental prostate cancers on short-term follow up.

PATIENTS AND METHODS

Complete data from 97 of 105 prostates from CP specimens were available. Prostates were thoroughly analysed and sectioned at 2 mm intervals. PSA levels and the findings at digital rectal examination before surgery were obtained prospectively. None of the patients had any evidence of prostate cancer before CP.

RESULTS

Incidental prostate cancer was detected in 58 of 97 (60%) of the CP specimens; of these, 31 (53%) were significant according to the definition of Stamey et al. There was a weak correlation between tumour volume and PSA level, weighted solely by the four larger-volume cancers. The median PSA level for patients with and without prostate cancer was not significantly different (3.1 vs 1.1 ng/mL, P = 0.06). The follow-up of the 35 patients alive with prostate cancer showed four PSA recurrences (PSA >0.02 ng/mL) with one distant metastasis after a median follow-up of 3 years. None of the patients with insignificant tumours developed biochemical recurrence.

CONCLUSIONS

The weak correlation between PSA level and tumour volume in these patients supports the argument that PSA is largely produced by benign prostatic hyperplasia and is therefore a poor screening tool for asymptomatic healthy men. Most incidental prostate cancers in CP specimens are significant, contrary to previous analyses, but have little practical importance in terms of oncological outcome.

The role of transbronchial fine needle aspiration in an integrated care pathway for the assessment of patients with suspected lung cancer

Transbronchial fine needle aspiration (TBNA) is a simple technique for sampling mediastinal lymph nodes and may provide additional information in patients with suspected lung cancer. However, the technique is still under-utilized, and the objective of this study was to evaluate the value of TBNA as part of an integrated pathway for the assessment of patients with suspected lung cancer. All patients referred to the lung cancer services of our institutions were prospectively evaluated. TBNA was performed in all patients with evidence of mediastinal lymphadenopathy. TBNA of one or more lymph node sites were performed in 129 of these patients. TBNA was the sole diagnostic modality in 23% of patients and provided positive staging information for 49% of patients, with adequate sampling in 71% of patients. Among patients with mediastinal adenopathy, the number of patients who required a TBNA performed to diagnose one patient with malignancy in patients suspected with lung cancer (number needed to diagnose) was 1.47 (95% confidence interval, 1.47-1.76). No complications were observed in patients who underwent TBNA. TBNA improves the diagnostic yield and staging of patients with lung cancer. Moreover, it is a simple, low-cost, and safe test, which should be incorporated into the diagnostic pathway of patients with suspected lung cancer.

Intra-operative assessment of excision margins using breast imprint and scrape cytology

Local recurrence in breast cancer surgery is related to the completeness of excision. Histological analysis of excision margins is time consuming and impractical for use intra-operatively. Our group evaluated breast imprint and scrape cytology (ISC) for the assessment of excision margins in a feasibility study in 1993-4, with 10 year clinical follow-up. Twenty-six consecutive women undergoing 27 wide local excisions for breast cancer had excision margins prospectively assessed with intra-operative ISC blinded to histology. All ISC results were ready (range 22-30 min) before surgery was completed. ISC agreed with histology in 21/27 (=78%) and disagreed in 6/27 (=22%) of the cases. In two cases with local recurrence, histology was positive in one case, whereas ISC margins were positive in both. Intra-operative ISC is reliable and could help the surgeon to excise more tissue to prevent a second (re-excision) operation. ISC margins may predict clinical outcome, although a larger interventional follow-up study is required.

Purified malignant mammary epithelial cells maintain hormone responsiveness in culture

Currently, the therapy for breast cancer is determined by immunohistochemical staining of the primary tumour for oestrogen receptor alpha (ERalpha). However, a proportion of ERalpha-positive patients fail to respond to tamoxifen and a proportion of ERalpha-negative patients show response. Here, we describe a novel procedure for the purification of malignant breast epithelial cells in an attempt to identify these patients at an early stage. Using this procedure, we are able to purify malignant cells to >90% purity as determined by immunohistochemical staining, cytology and fluorescent in situ hybridisation (FISH). While the malignant cells can be maintained in culture they do not proliferate in contrast to purified breast epithelial cells from reduction mammoplasties. Moreover, ERalpha and progesterone receptor (PR) expression is maintained in malignant cells, whereas normal epithelial cells rapidly lose ERalpha and PR. Functional studies were performed on the separated malignant cells in terms of their response to oestradiol and tamoxifen. Four out of the seven ERalpha-positive tumours showed a significant reduction in cell numbers after tamoxifen treatment compared to oestradiol, ERalpha negative tumours failed to show a response. We conclude that (a) it is possible to purify and maintain breast cancer cells for a sufficient period to permit functional studies and (b) ERalpha is retained in culture facilitating the use of these cells in studies of the mechanism of endocrine response and resistance in vitro.

Proliferative activity and p53 expression in primary and recurrent pterygia

PURPOSE

To assess p53 expression and proliferative activity in primary and recurrent pterygia from the same eyes.

DESIGN

Retrospective comparative human tissue study.

PARTICIPANTS

Tissue from excised primary pterygia that did not recur (group A, n = 10) was compared with tissue from primary pterygia that recurred (group B, n = 10) and to the recurrent pterygia tissue that was excised from subjects in group B (group C, n = 10). Ten normal conjunctivas served as controls (group D).

METHODS

Sections from each pterygium were immunostained with the MIB-1 and bp53. 12 monoclonal antibodies that react with Ki-67 and p53 antigens, respectively.

MAIN OUTCOME MEASURES

Proliferative activity was calculated as the mean of the MIB-1 positive cell count per eyepiece grid in high magnification (x40) (positive cell count/grid). Percentage of positive cells of all cells in the grid area was evaluated in the p53-stained sections.

RESULTS

Proliferative activity was found in the epithelium overlying the pterygia and normal conjunctiva. The mean MIB-1 positive cell count/grid +/- standard error was 2.84 +/- 1.07, 1.74 +/- 0.82, 3.83 +/- 1.35, and 0.86 +/- 0.33 in groups A, B, C, and D, respectively (P = 0.17, Kruskal-Wallis). P53 staining was found in 50% of pterygia in groups A, B, and C; none of the normal conjunctival tissues showed p53 immunoreactivity. Four of five p53-positive tissues in group B were p53-negative in group C. In the p53-positive pterygia, less than 10% of cells were p53 positive. However, p53-positive pterygia had higher mean MIB-1 positive cell count/grid +/- standard error as compared with the p53-negative lesions, 4.56 +/- 0.94 vs 1.39 +/- 0.59 (P = 0.021, Mann-Whitney).

CONCLUSIONS

p53 immunoreactivity and high proliferative activity in the epithelium overlying the pterygium are not associated with recurrence of pterygium.

Comparison of microcirculation patterns and MIB-1 immunoreactivity in iris and posterior uveal melanoma

PURPOSE

To compare melanomas confined to the iris and those involving either the ciliary body or choroid for the histologic features of microcirculation patterns and tumor cell proliferation indices.

DESIGN

Retrospective comparative human tissue study.

PARTICIPANTS

Ninety-eight uveal melanomas were studied, including 18 tumors confined to the iris, 30 tumors involving the ciliary body, and 50 tumors confined to the choroid.

METHODS

Formalin-fixed, paraffin-embedded sections from each tumor were stained with hematoxylin-eosin and with periodic acid-Schiff. Adjacent histologic sections were stained with the MIB-1 antibody that reacts with the Ki-67 antigen.

MAIN OUTCOME MEASURES

Microcirculation patterns were assessed in the periodic acid-Schiff-stained sections. Proliferative activity was assessed in the MIB-1-stained sections. The mean MIB-1 positive cell count per high-power field (HPF) was calculated in 10 HPF (x 40) in the area of maximal immunoreactivity. Two observers evaluated each MIB-1-stained section, and the interobserver reproducibility was assessed.

RESULTS

Histologic microcirculation patterns associated with death from metastatic disease in ciliary body and choroidal melanomas (parallel vessels with cross-linking and networks of back-to-back loops) were not found in any of the iris melanomas. By contrast, 34% and 63% of the choroidal and ciliary body melanomas, respectively, showed at least one of these patterns. The mean positive cell count per HPF +/- standard error was 19.9 +/- 3.5, 27 +/- 5.3, and 1.9 +/- 0.4 in choroidal, ciliary body, and iris melanoma, respectively (P: = 0.003, Kruskal-Wallis test).

CONCLUSIONS

Melanoma confined to the iris is characterized by a low rate of proliferation and the histologic absence of microcirculation patterns associated with metastatic posterior uveal melanoma. Both features are consistent with the relatively benign nature of iris lesions compared with melanomas involving the ciliary body or choroid.

Immunostaining of the estrogen receptor in conjunctival primary acquired melanosis

Conjunctival primary acquired melanosis (PAM) is a frequent precursor of conjunctival melanoma. Since there is indirect evidence that the conjunctiva is an estrogen-responsive tissue, and since it was suspected that estrogen has a role in the etiology of melanoma, we decided to evaluate whether PAM may be responsive to estrogen. Formalin-fixed, paraffin-embedded sections from 13 cases of PAM and 2 cases of conjunctival melanoma were immunostained with an estrogen-receptor (ER)-specific antibody. All lesions and the normal conjunctival tissue adjacent to the lesions were found to be ER negative. It is concluded that PAM and normal conjunctiva are not sensitive directly to estrogen. When considering previously reported data, it is conceivable that the normal conjunctiva, but not PAM, is indirectly affected by estrogen.

A transcription-activating polymorphism in the ACHE promoter associated with acute sensitivity to anti-acetylcholinesterases

Hypersensitivity to acetylcholinesterase inhibitors (anti-AChEs) causes severe nervous system symptoms under low dose exposure. In search of direct genetic origin(s) for this sensitivity, we studied six regions in the extended 22 kb promoter of the ACHE gene in individuals who presented adverse responses to anti-AChEs and in randomly chosen controls. Two contiguous mutations, a T-->A substitution, disrupting a putative glucocorticoid response element, and a 4-bp deletion, abolishing one of two adjacent HNF3 binding sites, were identified 17 kb upstream of the transcription start site. Allele frequencies for these mutations were 0.006 and 0.012, respectively, in 333 individuals of various ethnic origins, with a strong linkage between the deletion and the biochemically neutral H322N mutation in the coding region of ACHE. Heterozygous carriers of the deletion included a proband who presented with acute hypersensitivity to the anti-AChE pyridostigmine and another with unexplained excessive vomiting during a fourth pregnancy following three spontaneous abortions. Electromobility shift assays, transfection studies and measurements of AChE levels in immortalized lymphocytes as well as in peripheral blood from both carriers and non-carriers, revealed functional relevance for this mutation both in vitro and in vivo and showed it to increase AChE expression, probably by alleviating competition between the two hepatocyte nuclear factor 3 binding sites. Moreover, AChE-overexpressing transgenic mice, unlike normal FVB/N mice, displayed anti-AChE hypersensitivity and failed to transcriptionally induce AChE production following exposure to anti-AChEs. Our findings point to promoter polymorphism(s) in the ACHE gene as the dominant susceptibility factor(s) for adverse responses to exposure or to treatment with anti-AChEs.

In vivo and in vitro resistance to multiple anticholinesterases in Xenopus laevis tadpoles

Natural and man-made anticholinesterases comprise a significant share of the Xenobiotic poisons to which many living organisms are exposed. To evaluate the potential correlation between the resistance of acetylcholinesterase (AChE) to such toxic agents and the systemic toxicity they confer, we characterized the sensitivity of AChE from Xenopus laevis tadpoles to inhibitors, examined the susceptibility of such tadpoles to poisoning by various anticholinesterases and tested the inhibitor sensitivities of recombinant human AChE produced in these amphibian embryos from microinjected DNA. Our findings reveal exceptionally high resistance of Xenopus AChE to carbamate, organophosphate and quaternary anticholinesterases. In spite of the effective in vivo penetrance to Xenopus tadpole tissues of paraoxon, the poisonous metabolite of the pro-insecticide parathion, the amphibian embryos displayed impressive resistance to this organophosphorous agent. The species specificity of this phenomenon was clearly displayed in Xenopus tadpoles expressing recombinant human AChE, which was far more sensitive than the frog enzyme to in vivo paraoxon inhibition. Our findings demonstrate a clear correlation between AChE susceptibility to enzymatic inhibition and the systemic toxicity of anticholinesterases and raise a serious concern regarding the use of Xenopus tadpoles for developmental toxicology tests of anticholinesterases.

MIB-1 and PC-10 immunostaining for the assessment of proliferative activity in primary acquired melanosis without and with atypia

AIMS

To compare the proliferative activity of intraepithelial melanocytes in primary acquired melanosis (PAM) without atypia and PAM with atypia by immunohistochemical staining for the Ki-67 antigen and the proliferating cell nuclear antigen (PCNA).

METHODS

Formalin fixed, paraffin embedded sections from 35 archival specimens of PAM without atypia (n = 19) and with atypia (n = 16) were studied by immunostaining with MIB-1 and PC-10 monoclonal antibodies that react with the Ki-67 antigen and PCNA respectively. The results were calculated as the mean number of positive cells per eyepiece grid. All specimens were evaluated by two masked observers, and the interobserver reproducibility was assessed.

RESULTS

The means of the positive cell count in PAM with atypia were significantly higher compared with PAM without atypia for both observers, in both the PC-10 and the MIB-1 stained sections. In a linear least square model that estimated the interobserver and between group variation, the difference of MIB-1 and PC-10 positive cell count between PAM without and with atypia remained highly significant. The difference between the observers was not significant.

CONCLUSIONS

Immunostaining with MIB-1 and PC-10 demonstrated that PAM with atypia has higher proliferative activity than PAM without atypia. This method was found to be reproducible between different observers.

Systemic lupus erythematosus associated with acute Epstein-Barr virus infection

Systemic lupus erythematosus (SLE) is a multisystem disease of unknown origin, characterized by a variety of autoimmune phenomena. Viruses have long been postulated to play a role in its pathogenesis. Several observations suggested a link between Epstein-Barr virus (EBV) and SLE. We describe a 14-year-old girl who presented with acute onset of SLE concurrently with clinical and laboratory findings consistent with EBV-induced infectious mononucleosis (IM). Evidence for acute EBV infection was confirmed by serological studies and detection of specific EBV antigens on kidney biopsy. This close association between EBV and SLE suggests a possible role of the virus in the pathogenesis of SLE in this patient.

Pregnancy associated with colon carcinoma overexpressing p53

The development of colon carcinoma during pregnancy is a rare event. However, when colon carcinoma develops during pregnancy it is considered a lethal coincidence due to rapid progression. We report two rare cases of colon adenocarcinoma diagnosed during gestation. Both tumors displayed increased nuclear immunostaining for p53. The increased expression of p53 in tumor cells could indicate that the p53 gene is either mutated or stabilized or alternatively overexpressed as a responses to DNA damage. It is hypothesized that the development of colon carcinoma during pregnancy can be attributed to alterations of the p53 tumor suppressor gene or gene product on one hand and a maternal immune-tolerant state on the other.

Diagnostic role of cytology in screen-detected breast cancer

Fine-needle aspiration cytology (FNAC) of the breast was performed in 491 patients over a 3-year period. Some 365 examinations (74.3 percent) were performed by palpation and the remaining 126 (25.7 percent) by stereotaxis. Ninety-six patients were excluded because of inadequate follow-up. Using a standard method of reporting the results 247 smears were classified as C1 and C2, but based on clinical and radiological criteria excision biopsy was recommended and performed in 122 patients with these lesions. Twenty-two per cent of C2 lesions were found to be malignant after histological examination. Forty-two patients with C3 or C4 cytology were advised to have excision biopsy and 41 had surgery. In all but one case the lesion was found to be malignant histologically. Definitive surgery was performed on 106 patients with C5 cytology and the diagnosis of malignancy was confirmed histologically in 105 of them. FNAC is a useful diagnostic tool in breast screening but in view of the number of false-negative results, cytology alone is unreliable and, therefore, full triple assessment is recommended.

Sanctuary of hepatitis B virus in bone-marrow cells of patients undergoing liver transplantation

Hepatitis B virus (HBV) reinfection after liver transplantation is a major problem. HBV is mainly a hepatotrophic virus but replicates in many extrahepatic tissues. We present here two cases of infected patients who underwent liver transplantation. Both underwent bone marrow (BM) and liver biopsies after transplantation. Biopsy specimens were stained for hepatitis B surface antigen (HB-sAg), and bone marrow aspirates and were separated for all subsets of cells. In both cases, HBV DNA analysis detected DNA in all BM fractions after transplantation, but HBV recurrence was found only in one case. We suggest that graft reinfection after liver transplantation may be caused by active replication of HBV in extrahepatic tissues and that BM cells are probably one of the major sanctuaries. The use of immunoprophylaxis based on BM-HBV studies is discussed.

Parathyroid hormone mRNA levels are increased by progestins and vary during rat estrous cycle

Estrogen increases parathyroid hormone (PTH) mRNA levels in vivo in ovariectomized rats. We now show that the 19-norprogestin R-5020 given to weanling rats or mature ovariectomized rats led to a twofold increase in thyroparathyroid PTH mRNA levels. This increase in PTH mRNA occurred at 24 and 48 h after progesterone but not at 72 h. There were no changes in serum calcium. In vitro, in primary cultures of bovine parathyroid cells, progesterone increased PTH mRNA levels threefold at 10(-8) M and twofold at 10(-9) M after 24 h. Progesterone receptor (PR) mRNA was demonstrated in rat parathyroid tissue by in situ hybridization and in human parathyroid adenoma by immunohisto-chemistry. Changes in PTH mRNA levels during the rat estrous cycle were also studied. At proestrus and estrus PTH mRNA levels were increased significantly by three- and fourfold compared with diestrus. Our results confirm that the parathyroid gland is a target organ for the ovarian sex steroids estrogen and progesterone and are of physiological relevance as shown by the changes during estrus.

Parathyroid cell proliferation in normal and chronic renal failure rats. The effects of calcium, phosphate, and vitamin D

Secondary hyperparathyroidism is characterized by an increase in parathyroid (PT) cell number, and parathyroid hormone (PTH) synthesis and secretion. It is still unknown as to what stimuli regulate PT cell proliferation and how they do this. We have studied rats with dietary-induced secondary hyper- and hypoparathyroidism, rats given 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and rats after 5/6 nephrectomy for the presence of PT cell proliferation and apoptosis. PT cell proliferation has been measured by staining for proliferating cell nuclear antigen (PCNA) and apoptosis by in situ detection of nuclear DNA fragmentation and correlated with serum biochemistry and PTH mRNA levels. A low calcium diet led to increased levels of PTH mRNA and a 10-fold increase in PT cell proliferation. A low phosphate diet led to decreased levels of PTH mRNA and the complete absence of PT cell proliferation. 1,25 (OH)2D3 (25 pmol/d x 3) led to a decrease in PTH mRNA levels and unlike the hypophosphatemic rats there was no decrease in cell proliferation. There were no cells undergoing apoptosis in any of the experimental conditions. The secondary hyperparathyroidism of 5/6 nephrectomized rats was characterized by an increase in PTH mRNA levels and PT cell proliferation which were both markedly decreased by a low phosphate diet. The number of PCNA positive cells was increased by a high phosphate diet. Therefore hypocalcemia, hyperphosphatemia and uremia lead to PT cell proliferation, and hypophosphatemia completely abolishes this effect. Injected 1,25 (OH)2D3 had no effect. These findings emphasize the importance of a normal phosphate and calcium in the prevention of PT cell hyperplasia.

Plasma and tumor prolactin in colorectal cancer patients

Fifteen consecutive patients with recently diagnosed colorectal cancer were studied for plasma and tumor tissue prolactin content. In eight patients (four men and four postmenopausal females), preoperative high plasmatic prolactin was found (mean 1553 nmol; range 516-3677 nmol). In three of them, prolactin was also present in the tumor cells. All plasma prolactin levels returned to normal after tumor resection and remained so during a three-month follow-up. The tumor stage by Duke distribution was similar for both high and normal plasmatic prolactin patients. The role of prolactin in the pathogenesis of colorectal cancer, and as a marker of the tumor, remains to be established. This is the first time that prolactin has been detected in human colon cancer.

p53 expression in patients with cirrhosis with and without hepatocellular carcinoma

BACKGROUND

Mutated p53 acts as a dominant oncogene, whereas the wild type (wt) p53 gene product suppresses cell growth. Abnormalities in the p53 gene are reported in more than 50% of malignant tumors. Recently, an allelic loss of chromosome 17p, where the p53 gene is located, was found to be more frequent in hepatocellular carcinoma (HCC) cell lines and human tumors. In addition, in half of the cases of HCC from endemic areas for hepatitis B virus and aflatoxin, a hot spot point mutation at codon 249 was detected, as previously reported. Missense mutations in p53, mdm-2 complex formation, and other unknown mechanisms may lead to stabilization of the gene product, thus rendering it detectable by immunohistochemistry.

METHODS

To assess the relationship between p53 status at a premalignant stage and in HCC, the authors studied the immunohistologic expression of p53 in HCC and in the adjacent nontumorous resected liver tissue, using monoclonal antibody to wt and mutated p53.

RESULTS

Twelve of the 14 patients with liver tumors had HCC. Of the 12 patients with HCC and underlying cirrhosis, 8 (67%) had increased p53 expression in HCC cells. Eight of the 12 patients with p53-positive HCC cells had p53 overexpression in the nontumorous hepatocytes within regenerative nodules adjacent to HCC tissue. Three of 21 cirrhotic livers without a detectable tumor had increased p53 expression in the regenerative nodules. None of the 12 patients with chronic active hepatitis without cirrhosis or the 13 with a normal liver histology had increased p53 expression.

CONCLUSION

p53 overexpression in some cirrhotic livers and in nontumorous livers of patients with HCC may indicate a normal p53 gene response to cellular stress or, alternatively, to an abnormally or mutated p53 gene, and could occur before the development of HCC.

p53 expression in patients with cirrhosis with and without hepatocellular carcinoma

BACKGROUND

Mutated p53 acts as a dominant oncogene, whereas the wild type (wt) p53 gene product suppresses cell growth. Abnormalities in the p53 gene are reported in more than 50% of malignant tumors. Recently, an allelic loss of chromosome 17p, where the p53 gene is located, was found to be more frequent in hepatocellular carcinoma (HCC) cell lines and human tumors. In addition, in half of the cases of HCC from endemic areas for hepatitis B virus and aflatoxin, a hot spot point mutation at codon 249 was detected, as previously reported. Missense mutations in p53, mdm-2 complex formation, and other unknown mechanisms may lead to stabilization of the gene product, thus rendering it detectable by immunohistochemistry.

METHODS

To assess the relationship between p53 status at a premalignant stage and in HCC, the authors studied the immunohistologic expression of p53 in HCC and in the adjacent nontumorous resected liver tissue, using monoclonal antibody to wt and mutated p53.

RESULTS

Twelve of the 14 patients with liver tumors had HCC. Of the 12 patients with HCC and underlying cirrhosis, 8 (67%) had increased p53 expression in HCC cells. Eight of the 12 patients with p53-positive HCC cells had p53 overexpression in the nontumorous hepatocytes within regenerative nodules adjacent to HCC tissue. Three of 21 cirrhotic livers without a detectable tumor had increased p53 expression in the regenerative nodules. None of the 12 patients with chronic active hepatitis without cirrhosis or the 13 with a normal liver histology had increased p53 expression.

CONCLUSION

p53 overexpression in some cirrhotic livers and in nontumorous livers of patients with HCC may indicate a normal p53 gene response to cellular stress or, alternatively, to an abnormally or mutated p53 gene, and could occur before the development of HCC.

Clonal analysis of three morphologically distinct lymphomas occurring in the same patient

AIMS

To determine whether three morphologically distinct lymphomas (mucosa associated lymphoid tissue (MALT) lymphoma, monocytoid B cell lymphoma, and large cell anaplastic lymphoma), which occurred in the same patient, were in fact three morphological variants of the same lymphoproliferative process.

METHODS

Previously described methods of clonal analysis using the polymerase chain reaction (PCR) were used to determine the pattern of rearrangements of the immunoglobulin heavy chain gene and the T cell receptor beta and T cell receptor gamma chain genes in the three lymphomas.

RESULTS

All three morphological entities had identical patterns of gene rearrangements.

CONCLUSIONS

This finding confirms the association between MALT lymphoma and monocytoid B cell lymphoma, and also provides evidence that large cell anaplastic lymphoma may not only arise de novo but may also be an end stage morphological picture in lymphoma progression.

Hepatitis B virus infection associated with hematopoietic tumors

Hepatitis B virus (HBV) infection and replication have been linked to the development of hepatocellular carcinoma. Bone marrow-derived cells, as well as mesenchymal and epithelial cells, were recently shown to support HBV replication. We hypothesize that the mechanism that links HBV infection and liver tumors might also promote tumor development in tissues permissive for HBV replication. Between 1980 and 1993 we retrospectively identified 22 patients who were hepatitis B surface antigen (HBsAg) carriers and had extra-hepatic malignancies. These patients had 25 tumors, of which 22 were bone marrow derived. HBsAg was detected by immunohistochemistry in bone marrow cells of leukemia patient and of 3 of 10 lymphoma patients. In addition, in 4 of 10 patients with lymphoma, including 2 patients in which HBsAg stained bone marrow cells, HBsAg was also detected in the endothelial cells of blood vessels of the tumor tissue. These results suggest that the identification of an HBV gene product in endothelial cells might point to a role of HBV infection in the development of certain hematopoietic tumors, possibly through activation of cytokines or growth factors, which may eventually lead to bone marrow cell proliferation.

Trophoblasts circulating in maternal blood as candidates for prenatal genetic evaluation

Trophoblasts have been detected in uterine venous blood, lung parenchyma and maternal blood in the first trimester. Their dilution within maternal leukocytes has been recently estimated to be 1:10(-6). The objectives of this study were to enrich peripheral maternal blood preparations for trophoblast cells, to isolate trophoblasts from the enriched preparation by highly specific markers and to assess fetal cell total number of chromosomal copies by fluorescence in-situ hybridization (FISH). Negative and positive selections for trophoblasts were performed. To assess the efficacy of the enrichment methods, a model mimicking the in-vivo conditions was established. Purified first trimester trophoblasts were prepared from first trimester placentas and were mixed with leukocytes from non-pregnant women in various concentrations. Magnetic beads coupled with antibodies to the common leukocyte antigen (CD45) or to antitrophoblast specific antigens (Trop1, Trop2 and GB25), were attached to peripheral maternal blood cells or to the prepared mixed cell populations. The expression of alpha human chorionic gonadotrophin (alpha HCG) or of human placental lactogen (HPL) by the remaining cells was examined by two means: (i) immunocytochemistry, using monoclonal antibodies against HPL and alpha HCG to stain fetal cells; (ii) reverse transcriptase polymerase chain reaction (RT-PCR), using specific primers for exons of the HPL or alpha HCG mRNAs. Results revealed that HPL- and alpha HCG-expressing cells could be identified in maternal blood only in very rare instances. On the other hand, expression of alpha HCG and HPL by only 100 purified first trimester trophoblasts artificially mixed with peripheral leukocytes at a ratio of 1:10(-5) could be identified by both immunocytochemistry and RT-PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

PC-10 immunostaining of proliferating cell nuclear antigen in posterior uveal melanoma. Enucleation versus enucleation postirradiation groups

PURPOSE

It is difficult to assess the viability of uveal melanoma after radiotherapy treatment. The purpose of the current study is to investigate PC-10 monoclonal antibody of proliferating cell nuclear antigen as a possible marker for cell proliferation and tumor viability in conventionally processed histologic preparations of uveal melanoma irradiated by brachytherapy as well as in nonirradiated melanomas.

METHODS

Thirteen enucleated eyes with posterior uveal melanoma that were treated by brachytherapy (cobalt 60 or ruthenium 106 radioactive plaques) were included in this study. Thirteen enucleated eyes of the same size with nonirradiated posterior uveal melanoma served as controls. The tumors were stained with PC-10 monoclonal antibody to proliferating cell nuclear antigen. All clinical and histologic data of the tumors were recorded and analyzed.

RESULTS

Five of the irradiated tumors showed positive staining with PC-10, although with a low score. Four of these tumors showed regrowth, and the fifth tumor was treated with a low-irradiation dose (5500 rad). In the nonirradiated tumor group, nine were positive for PC-10 staining, with a higher score. Significant correlation was found in this group between the PC-10 score and the mitotic figure count, but not with other prognostic factors. In three of four tumors that caused metastatic death, the PC-10 staining was positive and had a high score.

CONCLUSIONS

PC-10 immunostaining is a simple, reproducible method that can be applicable to conventionally processed histologic preparations. It clearly shows that cellular proliferation activity in nonirradiated and irradiated uveal melanomas. Based on the small number of cases reported herein, it seems that the PC-10 score can correlate with prognosis, but further studies should be performed.

Estrogen receptors and biologic response in rat parathyroid tissue and C cells

The expression of the PTH and calcitonin genes is dramatically decreased by 1,25(OH)2D3 in vivo, and the PTH gene expression is increased by hypocalcemia. We have now studied the effect of estrogens on the expression of these genes in vivo. 17 beta-Estradiol, given to ovariectomized rats, led to a fourfold increase in PTH mRNA and calcitonin mRNA levels. These effects occurred 24 h after single injections of 37-145 nmol estradiol, or after constant infusions of 12 pmol/d for 1 or 2 wk, where there was no effect on serum calcium levels. The estrogen receptor mRNA was demonstrated in the thyroparathyroid tissue by polymerase chain reaction. The estrogen binding was localized to the parathyroid and C cells by immunohistochemistry. Uterus weight was increased by repeated larger doses (73 nmol/d x 7) of estradiol, but not by the small doses (12 pmol/d for 1 or 2 wk) which were effective on the PTH and calcitonin genes, suggesting a sensitive endocrine effect. These results confirm that the parathyroid and C cells are target organs for estrogen, leading to an increased expression of PTH and calcitonin, which by their combined anabolic effect on bone would help prevent osteoporosis.

Detection of occult nasopharyngeal primary tumours by means of in situ hybridization

Detection of nasopharyngeal carcinoma primaries in patients presenting with neck node metastases may sometimes demand considerable efforts. By using the 'in situ hybridization' technique, we manage to identify the Epstein-Barr virus in neck metastases secondary to nasopharyngeal carcinomas. We propose that such identification in neck node metastases where the primary lesion is unknown indicates a nasopharyngeal primary.

Immunocytochemical distribution of endogenous albumin and immunoglobulins in the glomerular wall of the sucrose-fed "Cohen" diabetic rat

Endogenous circulating albumin and immunoglobulin G (IgG) molecules were revealed with high resolution over the glomerular wall of renal tissue from normoglycemic and sucrose-fed hyperglycemic Cohen rats applying the protein A-gold immunocytochemical approach. Due to the length of the experiment, the hyperglycemic animals demonstrated only minor renal morphological alterations. In spite of this, labelling for albumin and immunoglobulins in the glomerular wall showed significant differences between the normoglycemic and hyperglycemic animals. In the former, the labelings were restricted to the endothelial side of the glomerular basement membrane, while in the latter, the labelings were distributed throughout the entire thickness of the basement membrane. In addition, the hyperglycemic animals display some labelling associated with the slit diaphragms between podocytes and in the urinary space. Numerous lysosomal structures present in podocytes and mesangial cells of the hyperglycemic animals were intensely labeled for albumin and IgGs, reflecting a reabsorption activity. Dense deposits labeled for IgGs were found in the glomerular wall and mesangial regions of hyperglycemic animals corresponding to depositions of immune-complexes. These results demonstrated that in hyperglycemic conditions induced by environmental factors such as the diet, the permselectivity of the glomerular basement membrane is lost; proteins such as albumin and IgGs are not restricted by the endothelial side of the basement membrane and cross the glomerular wall leading to proteinuria. The loss of selective permeability properties of the glomerular basement membrane was found to precede the morphological changes occurring in the glomerular wall during diabetes.

The use of monoclonal anti-CEA antibody immunohistochemistry in detecting the origin of oral cavity metastasis

A 75-year-old woman presented with a painless swelling in the right mandibular retromolar area and numbness of the left lower lip. Radiographic examination of the mandible demonstrated an osteolytic lesion of the ascending ramus. Biopsy revealed adenocarcinoma of obscure origin. Staining of the specimen with a monoclonal antibody specific to colon carcinoma revealed its origin. On subsequent examinations, a primary tumor in the rectosigmoid region with extensive lung, liver and skeletal metastases were diagnosed. This unusual case of colonorectal carcinoma, presenting as a metastatic lesion of the mandible, was readily diagnosed by a novel immunohistochemical technique that utilizes highly specific monoclonal antibodies.