Lynch/Turcot Syndrome and Sporadic Mismatch Repair Deficient High-Grade Gliomas – A Case Series

AIMS

The DNA mismatch repair (MMR) system is critical for genomic stability correcting errors generated during DNA replication with germline pathogenic variants (PVs) causing Lynch syndrome. Although acquired MMR deficiency is associated with temozolomide resistance, the incidence in treatment naïve tumours is unknown and not routinely screened for. Here we present three MMR deficient gliomas and describe their comprehensive molecular profile.

METHOD

Thirteen gliomas; 9/34 that had undergone sequencing of 50 cancer-associated genes and found to have frameshift/multiple point PVs, indicative of defective MMR, and four MSI-high tumours, identified following microsatellite analysis for 1p/19q co-deletion as part of routine care, were selected for analysis. MMR expression was then assessed by immunohistochemistry. Seven tumours showed loss of one or more MMR proteins and were molecularly characterised using PCR-based Promega MSI analysis and NGS-based Illumina TruSight500 panel.

RESULTS

Pathogenic variants in MMR genes and hypermutated phenotypes (TMB > 10mutations/Mb) were identified in three cases. One individual harboured an additional POLE PV resulting in an ultra-hypermutated phenotype (>100mutations/Mb). Two MMR PVs were germline, leading to a new diagnosis of Lynch syndrome. Only one of three tumours was found to be MSI-high using the Promega MSI analysis whilst all three were identified as MSI-high using TruSight500 MSI calling algorithms.

CONCLUSION

We describe the comprehensive molecular profile of seven treatment naïve gliomas, three being MMR deficient. We show TruSight500 to be more sensitive and reliable for detecting MSI compared to Promega. Given the implications, this additional analysis should be considered as part of the molecular report on all gliomas.

ELEVATE - evaluating Temozolomide and Nivolumab in patients with advanced unresectable previously treated oesophagogastric adenocarcinoma with MGMT methylation: study protocol for a single arm phase II trial

BACKGROUND

For patients with oesophagogastric adenocarcinoma, surgery is the only curative option and despite the use of multimodality therapy, which combines it with chemotherapy and/or radiotherapy, more than 50% of patients will relapse and die. Many UK patients present with advanced disease which is already inoperable or metastatic at diagnosis. For these patients, standard care chemotherapy only offers them survival of less than a year. Nivolumab, a checkpoint blockade inhibitor, has been found to work in some advanced cancers. It is proposed, for those where immunotherapy hasn't worked, that these immunologically evasive tumours need to be sensitized to immunotherapy drugs to allow them to act.

METHODS

ELEVATE is a single arm phase II trial testing the overall response to nivolumab following temozolomide treatment in patients with advanced unresectable previously treated adenocarcinoma which is O6-methylguanine-DNA-methyltransferase (MGMT) methylated. 18 patients are being recruited from UK secondary care sites. To be eligible, participants must have been treated with at least 3 months of platinum and fluoropyrimidine chemotherapy. Participants will receive 50 mg/m2 temozolomide continuously for 3 months. If their disease progresses during the 3 months, they will stop temozolomide and start nivolumab at a dose of 240mg every 2 weeks. If there is no progression after 3 months the participant will continue taking temozolomide in combination with nivolumab. All treatment will stop once the participant progresses on nivolumab. The primary endpoint is the best overall response to nivolumab, using both Response Evaluation Criteria in Solid Tumours version 1.1 and immunotherapy modified Response Evaluation Criteria in Solid Tumours. Secondary endpoints include progression-free survival, overall survival, and quality of life.

DISCUSSION

ELEVATE will provide evidence for whether giving nivolumab after temozolomide in patients with previously treated advanced oesophagogastric adenocarcinoma is safe and biologically effective prior to future randomised trials.

TRIAL REGISTRATIONS

EudraCT Number: 2020-004771-41 (issued 01 October 2020); ISCRTN11398887 (registered 14 July 2021).

Platelet derived growth factor receptor alpha (PDGFRA) mutant gastrointestinal stromal tumours (GISTs): Clinicopathological characteristics and outcomes from a regional centre in the United Kingdom

11534

Background: GISTs are the most common mesenchymal tumours of the gastrointestinal tract with an annual incidence of 10-15 per million. 10% of GISTS have activating mutations in the PDGFRA gene. We report our 13 year experience of all the PDGFRA-mutated GISTs in our regional centre in Cambridge. Methods: PDGFRA-mutant GISTs were identified from the Cambridge GIST database. Demographics, clinical and histopathological features, survival and response to tyrosine kinase inhibitors of all the patients from 2008-2021 were reviewed. Results: n = 50 (male:female 1.5:1) Median age 68 years (range 19-87). 8% of patients were under the age of 40 years. Tumour size ranged from 1-26 cm with a median of 5 cm. Mitotic index ranged from 1-51 with a median of 1 mitosis/5mm2. 52% of GISTs were located in the gastric body. Histological subtypes: 44% epithelioid, 36% mixed and 20% spindle cell. 38% of cases had high KIT expression (immunohistochemistry), whilst 48% had patchy expression and 14% were negative. Most were DOG1-positive (94%). 76% had radical surgery, 60% had laparoscopic resection. 24% were assessed as being high risk GISTs using the modified AFIP model contrasted to 13% being high risk with prognostic contour mapping. 13% developed metastatic disease with liver being the most common metastatic site. The table shows PDGFRA mutational analysis results: 58% had a D842V mutation. None had a KIT mutation. With a median follow up of 55.1 months, 82% were alive. 6 patients died from metastatic GIST and 3 from other causes. Median time to metastatic disease in resected GISTs was 30.1 months and median time from metastatic diagnosis to death was 18.5 months. Patients who presented with metastatic disease had poor survival compared with patients with localised disease ( p=0.001). 8 patients were treated with tyrosine kinase inhibitors including imatinib, sunitinib and regorafenib prior to 2020 with no objective responses. 3 patients were treated with Avapritinib since 2020 within the compassionate use programme. All 3 patients had partial responses and 2 patients are continuing Avapritinib with no grade 3 adverse events. Conclusions: We report the largest single centre PDGFRA-mutant GIST cohort from Europe. Male preponderance and exclusive gastric location were observed. KIT expression was patchy to negative in the majority of patients. 58% had PDGFRA D842V mutations for which Avapritinib has been recently approved. No objective responses were seen with imatinib, sunitinib or regorafenib. Our early experience with Avapritinib is promising.[Table: see text]

Familial wild-type gastrointestinal stromal tumour in association with germline truncating variants in both SDHA and PALB2

Gastrointestinal stromal tumour (GIST) is a mesenchymal neoplasm arising in the gastrointestinal tract. A rare subset of GISTs are classified as wild-type GIST (wtGIST) and these are frequently associated with germline variants that affect the function of cancer predisposition genes such as the succinate dehydrogenase subunit genes (SDHA, SDHB, SDHC, SDHD) or NF1. However, despite this high heritability, familial clustering of wtGIST is extremely rare. Here, we report a mother–son diad who developed wtGIST at age 66 and 34 years, respectively. Comprehensive genetic testing revealed germline truncating variants in both SDHA (c.1534C>T (p.Arg512*)) and PALB2 (c.3113G>A (p.Trp1038*)) in both affected individuals. The mother also developed breast ductal carcinoma in-situ at age 70 years. Immunohistochemistry and molecular analysis of the wtGISTs revealed loss of SDHB expression and loss of the wild-type SDHA allele in tumour material. No allele loss was detected at PALB2 suggesting that wtGIST tumourigenesis was principally driven by succinate dehydrogenase deficiency. However, we speculate that the presence of multilocus inherited neoplasia alleles syndrome (MINAS) in this family might have contributed to the highly unusual occurrence of familial wtGIST. Systematic reporting of tumour risks and phenotypes in individuals with MINAS will facilitate the clinical interpretation of the significance of this diagnosis, which is becoming more frequent as strategies for genetic testing for hereditary cancer becomes more comprehensive.

Breast cancer in multiple endocrine neoplasia type 1 (MEN1)

SUMMARY

A 38-year-old female was identified as carrying a heterozygous pathogenic MEN1 variant (c.1304delG) through predictive genetic testing, following a diagnosis of familial hyperparathyroidism. Routine screening for parathyroid and pituitary disease was negative. However, cross-sectional imaging by CT revealed a 41 mm pancreatic tail mass. Biopsy via endoscopic ultrasound confirmed the lesion to be a well-differentiated (grade 1) pancreatic neuroendocrine tumour (pNET) with MIB1<1%. Biochemically, hyperinsulinaemic hypoglycaemia was confirmed following an overnight fast, which was subsequently managed by diet alone prior to definitive surgery. Pre-operative work-up with octreotide SPECT CT demonstrated avid tracer uptake in the pancreatic lesion and, unexpectedly, a focal area of uptake in the left breast. Further investigation, and subsequent mastectomy, confirmed ductal carcinoma in situ pT2 (23 mm) grade 1, N0 (ER positive; HER2 negative). Following mastectomy, our patient underwent a successful distal pancreatectomy to resect the pNET. Loss of heterozygosity (LOH) at the MEN1 locus was found in both the breast tumour and pNET, thereby in keeping with a 'two-hit' hypothesis of oncogenesis, a suggestive but non-definitive clue for causation. To obtain further support for a causative relationship between MEN1 and breast cancer, we undertook a detailed review of the published literature which overall supports the notion that breast cancer is a MEN1-related malignancy that presents at a younger age and histologically, is typically of ductal subtype. Currently, clinical guidance regarding breast cancer surveillance in MEN1 does not exist and further research is required to establish a clinical and cost-effective surveillance strategy).

LEARNING POINTS

We describe a case of pNET and breast cancer diagnosed at a young age of 38 years in a patient who is heterozygous for a pathogenic MEN1 variant. Loss of the wild-type allele was seen in both breast tissue and pNET specimen. Breast cancer may be an under-recognised MEN1-associated malignancy that presents at a younger age than in the general population with a relative risk of 2-3. Further research is required to determine the cost-effectiveness of breast cancer surveillance approach at a younger age in MEN1 patients relative to the general population .

The role of [68 Ga]Ga-DOTATATE PET/CT in wild-type KIT/PDGFRA gastrointestinal stromal tumours (GIST)

BACKGROUND

[68 Ga]Ga-DOTATATE PET/CT is now recognised as the most sensitive functional imaging modality for the diagnosis of well-differentiated neuroendocrine tumours (NET) and can inform treatment with peptide receptor radionuclide therapy with [177Lu]Lu-DOTATATE. However, somatostatin receptor (SSTR) expression is not unique to NET, and therefore, [68 Ga]Ga-DOTATATE PET/CT may have oncological application in other tumours. Molecular profiling of gastrointestinal stromal tumours that lack activating somatic mutations in KIT or PDGFRA or so-called 'wild-type' GIST (wtGIST) has demonstrated that wtGIST and NET have overlapping molecular features and has encouraged exploration of shared therapeutic targets, due to a lack of effective therapies currently available for metastatic wtGIST.

AIMS

To investigate (i) the diagnostic role of [68 Ga]Ga-DOTATATE PET/CT; and, (ii) to investigate the potential of this imaging modality to guide treatment with [177Lu]Lu-DOTATATE in patients with wtGIST.

METHODS

[68 Ga]Ga-DOTATATE PET/CT was performed on 11 patients with confirmed or metastatic wtGIST and one patient with a history of wtGIST and a mediastinal mass suspicious for metastatic wtGIST, who was subsequently diagnosed with a metachronous mediastinal paraganglioma. Tumour expression of somatostatin receptor subtype 2 (SSTR2) using immunohistochemistry was performed on 54 tumour samples including samples from 8/12 (66.6%) patients who took part in the imaging study and 46 tumour samples from individuals not included in the imaging study.

RESULTS

[68 Ga]Ga-DOTATATE PET/CT imaging was negative, demonstrating that liver metastases had lower uptake than background liver for nine cases (9/12 cases, 75%) and heterogeneous uptake of somatostatin tracer was noted for two cases (16.6%) of wtGIST. However, [68 Ga]Ga-DOTATATE PET/CT demonstrated intense tracer uptake in a synchronous paraganglioma in one case and a metachronous paraganglioma in another case with wtGIST.

CONCLUSIONS

Our data suggest that SSTR2 is not a diagnostic or therapeutic target in wtGIST. [68 Ga]Ga-DOTATATE PET/CT may have specific diagnostic utility in differentiating wtGIST from other primary tumours such as paraganglioma in patients with sporadic and hereditary forms of wtGIST.

Investigating the clinical, pathological and molecular profile of oncocytic adrenocortical neoplasms: a case series and literature review

Background

Malignant oncocytic adrenocortical neoplasms (OANs) are rare tumours with a distinctive biological behaviour compared to conventional adrenocortical carcinoma (ACC). The current prognostic systems overestimate the malignant potential of these tumours, and guidance for surveillance and treatment strategies are lacking.

Aim

To evaluate the utility of clinical, pathological and molecular markers in predicting the biological behaviour and outcomes of malignant OANs.

Methods

A retrospective clinicopathological review of 10 histologically confirmed OANs was carried out. Whole exome sequencing (WES) of germline and paired tumour samples was performed for four of the ten OAN cases and compared to WES data from five cases of conventional ACC and data from The Cancer Genome Atlas. We reviewed all the cases of malignant OAN reported in the literature and compared to our case series.

Results

Eight (80%) tumours were classified as malignant, one borderline and one benign (Lin-Weiss-Bisceglia criteria, LWB). The malignant OAN were larger tumours and had higher MIB index and Helsinki scores. Molecular profiling identified a pathogenic germline variant in MSH6 in an individual in the OAN group. The OAN samples had a lower mutation burden compared to the ACC samples. Somatic driver variants were identified in OAN and ACC samples including a pathogenic missense variant in CTNNB1.

Conclusion

In this study, the LWB classification demonstrated sensitivity for the differentiation of benign from malignant OAN. Molecular profiling identified dysregulation in DNA repair and Wnt signalling pathways in both OAN and ACC samples, suggesting a molecular overlap between OAN and conventional ACC.

A review of the tumour spectrum of germline succinate dehydrogenase gene mutations: Beyond phaeochromocytoma and paraganglioma

The citric acid cycle, also known as the Krebs cycle, plays an integral role in cellular metabolism and aerobic respiration. Mutations in genes encoding the citric acid cycle enzymes succinate dehydrogenase, fumarate hydratase and malate dehydrogenase all predispose to hereditary tumour syndromes. The succinate dehydrogenase enzyme complex (SDH) couples the oxidation of succinate to fumarate in the citric acid cycle and the reduction of ubiquinone to ubiquinol in the electron transport chain. A loss of function in the succinate dehydrogenase (SDH) enzyme complex is most commonly caused by an inherited mutation in one of the four SDHx genes (SDHA, SDHB, SDHC and SDHD). This mechanism was first implicated in familial phaeochromocytoma and paraganglioma. However, over the past two decades the spectrum of tumours associated with SDH deficiency has been extended to include gastrointestinal stromal tumours (GIST), renal cell carcinoma (RCC) and pituitary adenomas. The aim of this review is to describe the extended tumour spectrum associated with SDHx gene mutations and to consider how functional tests may help to establish the role of SDHx mutations in new or unexpected tumour phenotypes.

Neurofibromatosis 1 (NF1) and gastrointestinal stromal tumors (GISTs): Five-year experience from a regional center in United Kingdom

11035

Background: NF1 is an inherited autosomal dominant condition characterised by multifocal neurofibromas, café au lait spots, Lisch nodules, freckling. GISTs are the most common mesenchymal tumour of the gastrointestinal tract occurring in NF1 patients. We present our 5 year experience of NF1 associated GISTs from a regional centre in United Kingdom. Methods: 15 patients with GISTs associated with NF1 syndrome were identified from the database. Clinical, pathological, molecular and treatment outcomes were analysed. Results: N = 15. Male-3 and female-12. Median age 46 years. 33% were multifocal and 67% unifocal. Primary site Stomach-6.6%, duodenum-33%, small bowel-67%, colon 6.6%. Presenting symptoms: Abdominal pain-47%, anemia/bleed-40% and incidental finding-13%. Tumour size 0.5-23 cm, median 9 cm. Mitotic index 0-15, median 4 mitoses/5mm2. Risk stratification-Low/intermediate risk 60% and high risk 40%. Histology was spindle cell in 87% and mixed in 13%. All GISTs were CD117 and DOG-1 +ve. SDHB expression was preserved in all GISTs. No activation mutations were detected in KIT (exons 9, 11, 13, 17), PDGFRA (exons 12, 14, 18) and BRAF. Treatment: 67% had the primary GIST resected. None had adjuvant imatinib. 6 patients had been treated with tyrosine kinase inhibitors. 1 partial response lasting < 3 months was observed with Imatinib. No durable responses were seen with Imatinib or Sunitinib or Regorafenib. All 5 patients with metastatic disease died within one year of diagnosis. Conclusions: GISTs associated with NF1 syndrome are rare. Median age of diagnosis is a decade earlier than KIT/PDGFRA mutated GISTs. We observed that NF1 associated GISTs occur predominantly in small bowel, are mostly spindle cell histology and have female preponderance. No durable responses were noted with Imatinib or Sunitinib or Regorafenib. There is an urgent need for systematic international collaboration to identify druggable pathways/targets in NF1 GISTs. Any trials should be multicentre/ multinational to expedite recruitment.

Contribution of immunoglobulin lambda light chain gene rearrangement analysis in the diagnosis of B-cell neoplasms

Identification of clonal IGH, IGK and IGL gene rearrangements offers diagnostic adjunct in suspected B-cell neoplasms. However, many centres omit IGL analysis as its value is uncertain. A review of 567 cases with IGH, IGK and IGL rearrangement assessed using BIOMED-2 assays showed clonal immunoglobulin gene rearrangement in 54% of cases, of which 24% had a clonal IGL rearrangement. In two cases, the clonal rearrangement was detected exclusively by IGL analysis. This finding demonstrates the added value of IGL analysis for clonality assessment, especially in suspected B-cell neoplasms in which a clonal IGH and/or IGK rearrangement is not detected or is equivocal.

Rapid disease progression in a patient with mismatch repair-deficient and cortisol secreting adrenocortical carcinoma treated with pembrolizumab

CONTEXT

Metastatic adrenocortical carcinoma (ACC) is an aggressive malignancy with a poor prognosis and limited therapeutic options. A subset of ACC is due to Lynch syndrome, an inherited tumor syndrome resulting from germline mutations in mismatch repair (MMR) genes. It has been demonstrated that several cancers characterized by MMR deficiency are sensitive to immune checkpoint inhibitors that target PD-1. Here, we provide the first report of PD-1 blockade with pembrolizumab in a patient with Lynch syndrome and progressive cortisol-secreting metastatic ACC.

CASE REPORT

A 58-year-old female with known Lynch syndrome presented with severe Cushing's syndrome and was diagnosed with a cortisol-secreting ACC. Three months following surgical resection and adjuvant mitotane therapy the patient developed metastatic disease and persistent hypercortisolemia. She commenced pembrolizumab, but her second cycle was delayed due to a transient transaminitis. Computed tomography performed after 12 weeks and 2 cycles of pembrolizumab administration revealed significant disease progression and treatment was discontinued. After 7 weeks, the patient became jaundiced and soon died due to fulminant liver failure.

CONCLUSION

Treatment of MMR-deficient cortisol-secreting ACC with pembrolizumab may be ineffective due to supraphysiological levels of circulating corticosteroids, which may in turn mask severe drug-induced organ damage.

Translating in vivo metabolomic analysis of succinate dehydrogenase deficient tumours into clinical utility

PURPOSE

Mutations in the mitochondrial enzyme succinate dehydrogenase (SDH) subunit genes are associated with a wide spectrum of tumours including phaeochromocytoma and paraganglioma (PPGL) 1, 2, gastrointestinal stromal tumours (GIST) 3, renal cell carcinoma (RCC) 4 and pituitary adenomas5. SDH-related tumorigenesis is believed to be secondary to accumulation of the oncometabolite succinate. Our aim was to investigate the potential clinical applications of MRI spectroscopy (1H-MRS) in a range of suspected SDH-related tumours.

PATIENTS AND METHODS

Fifteen patients were recruited to this study. Respiratory-gated single-voxel 1H-MRS was performed at 3T to quantify the content of succinate at 2.4 ppm and choline at 3.22 ppm.

RESULTS

A succinate peak was seen in six patients, all of whom had a germline SDHx mutation or loss of SDHB by immunohistochemistry. A succinate peak was also detected in two patients with a metastatic wild-type GIST (wtGIST) and no detectable germline SDHx mutation but a somatic epimutation in SDHC. Three patients without a tumour succinate peak retained SDHB expression, consistent with SDH functionality. In six cases with a borderline or absent peak, technical difficulties such as motion artefact rendered 1H-MRS difficult to interpret. Sequential imaging in a patient with a metastatic abdominal paraganglioma demonstrated loss of the succinate peak after four cycles of [177Lu]-DOTATATE, with a corresponding biochemical response in normetanephrine.

CONCLUSIONS

This study has demonstrated the translation into clinical practice of in vivo metabolomic analysis using 1H-MRS in patients with SDH-deficient tumours. Potential applications include non-invasive diagnosis and disease stratification, as well as monitoring of tumour response to targeted treatments.

Clinical and Molecular Features of Renal and Pheochromocytoma/Paraganglioma Tumor Association Syndrome (RAPTAS): Case Series and Literature Review

CONTEXT

The co-occurrence of pheochromocytoma (PC) and renal tumors was linked to the inherited familial cancer syndrome von Hippel-Lindau (VHL) disease more than six decades ago. Subsequently, other shared genetic causes of predisposition to renal tumors and to PC, paraganglioma (PGL), or head and neck paraganglioma (HNPGL) have been described, but case series of non-VHL-related cases of renal tumor and pheochromocytoma/paraganglioma tumor association syndrome (RAPTAS) are rare.

OBJECTIVE

To determine the clinical and molecular features of non-VHL RAPTAS by literature review and characterization of a case series.

DESIGN

A review of the literature was performed and a retrospective study of referrals for investigation of genetic causes of RAPTAS.

RESULTS

Literature review revealed evidence of an association, in addition to VHL disease, between germline mutations in SDHB, SDHC, SDHD, TMEM127, and MAX genes and RAPTAS [defined here as the co-occurrence of tumors from both classes (PC/PGL/HNPGL and renal tumors) in the same individual or in first-degree relatives]. In both the literature review and our case series of 22 probands with non-VHL RAPTAS, SDHB mutations were the most frequent cause of non-VHL RAPTAS. A genetic cause was identified in 36.3% (8/22) of kindreds.

CONCLUSION

Renal tumors and PC/PGL/HNPGL tumors share common molecular features and their co-occurrence in an individual or family should prompt genetic investigations. We report a case of MAX-associated renal cell carcinoma and confirm the role of TMEM127 mutations with renal cell carcinoma predisposition.

Glucagon-like petide-2 acts on colon cancer myofibroblasts to stimulate proliferation, migration and invasion of both myofibroblasts and cancer cells via the IGF pathway

Glucagon-like peptide (GLP)-2 stimulates intestinal epithelial proliferation by acting, in part, via IGF release from sub-epithelial myofibroblasts. The response of myofibroblasts to GLP-2 remains incompletely understood. We studied the action of GLP-2 on myofibroblasts from colon cancer and adjacent tissue, and the effects of conditioned medium from these cells on epithelial cell proliferation, migration and invasion. GLP-2 stimulated proliferation, migration and invasion of myofibroblasts and the proliferative and invasive responses of cancer-associated myofibroblasts were greater than those of myofibroblasts from adjacent tissue. The responses were inhibited by an IGF receptor inhibitor, AG1024. Conditioned medium from GLP-2 treated myofibroblasts increased proliferation, migration and invasion of SW480, HT29, LoVo epithelial cells and these responses were inhibited by AG1024; GLP-2 alone had no effect on these cells. In addition, when myofibroblasts and epithelial cells were co-cultured in Ibidi chambers there was mutual stimulation of migration in response to GLP-2. The latter increased both IGF-1 and IGF-2 transcript abundance in myofibroblasts. Moreover, a number of IGF binding proteins (IGFBP-4, -5, -7) were identified in myofibroblast medium; in the presence of GLP-2 there was increased abundance of the cleavage products of IGBBP-4 and IGFBP-5 suggesting activation of a degradation mechanism that might increase IGF bioavailability. The data suggest that GLP-2 stimulates cancer myofibroblast proliferation, migration and invasion; GLP-2 acts indirectly on epithelial cells partly via increased IGF expression in myofibroblasts and partly, perhaps, by increased bioavailability through degradation of IGFBPs.

Sellar collision tumor involving pituitary gonadotroph adenoma and chondroma: a potential clinical diagnosis

We report on a 74-year-old male patient who presented with progressive neuroophthalmologic symptoms soon after the administration of a long-acting gonadotropin-releasing hormone agonist for treatment of a prostate cancer. Imaging revealed a destructively growing and extensively calcified sellar mass inconsistent with a pituitary adenoma. A transseptal transsphenoidal tumor mass reduction yielded a histological diagnosis of a collision tumor comprised of a gonadotroph adenoma intermingled with osteochondroma. We discuss a potential causal relationship between the administration of the long-acting gonadotropin-releasing hormone agonist and the sudden appearance of the previously unsuspected sellar lesion. Although the association of these two tumors is very likely coincidental, the possibility of causal relationship is addressed.

Intratumoral budding as a potential parameter of tumor progression in mismatch repair-proficient and mismatch repair-deficient colorectal cancer patients

In colorectal cancer, tumor budding at the invasive front (peritumoral budding) is an established prognostic parameter and decreased in mismatch repair-deficient tumors. In contrast, the clinical relevance of tumor budding within the tumor center (intratumoral budding) is not yet known. The aim of the study was to determine the correlation of intratumoral budding with peritumoral budding and mismatch repair status and the prognostic impact of intratumoral budding using 2 independent patient cohorts. Following pancytokeratin staining of whole-tissue sections and multiple-punch tissue microarrays, 2 independent cohorts (group 1: n = 289; group 2: n = 222) with known mismatch repair status were investigated for intratumoral budding and peritumoral budding. In group 1, intratumoral budding was strongly correlated to peritumoral budding (r = 0.64; P < .001) and less frequent in mismatch repair-deficient versus mismatch repair-proficient cases (P = .177). Sensitivity and specificity for lymph node positivity were 72.7% and 72.1%. In mismatch repair-proficient cancers, high-grade intratumoral budding was associated with right-sided location (P = .024), advanced T stage (P = .001) and N stage pN (P < .001), vascular invasion (P = .041), infiltrating tumor margin (P = .003), and shorter survival time (P = .014). In mismatch repair-deficient cancers, high intratumoral budding was linked to higher tumor grade (P = .004), vascular invasion (P = .009), infiltrating tumor margin (P = .005), and more unfavorable survival time (P = .09). These associations were confirmed in group 2. High-grade intratumoral budding was a poor prognostic factor in univariate (P < .001) and multivariable analyses (P = .019) adjusting for T stage, N stage distant metastasis, and adjuvant therapy. These preliminary results on 511 patients show that intratumoral budding is an independent prognostic factor, supporting the future investigation of intratumoral budding in larger series of both preoperative and postoperative rectal and colon cancer specimens.

Frequent expression of the breast differentiation antigen NY-BR-1 in mammary and extramammary Paget's disease

While mammary Paget's disease (MPD) is clearly linked to breast cancer, the histogenesis of extramammary Paget's disease (EMPD) is controversial. Recently NY-BR-1, a differentiation antigen expressed in the breast and in skin adnexal structures was identified. Its protein expression is restricted to normal and neoplastic breast epithelium and to adnexal tumors of the skin. In this study, we examine NY-BR-1 expression by immunohistochemistry in 24 MPD cases with synchronous ductal carcinoma in situ or invasive breast cancer. Results were compared with 26 cases of EMPD of men (n= 4) and women (n= 22) as well as in apoeccrine glands of the axilla and mammary-like glands of the anogenital region. We found NY-BR-1 positivity in 18 of 24 MPD (75%) and in 21 of 26 EMPD (80.8%). All apoeccrine glands of the axilla and mammary-like glands of the anogenital region were NY-BR-1-positive. NY-BR-1 expression is a common finding in MPD and in EMPD. When considering the diagnosis of Paget's disease, NY-BR-1 is a useful diagnostic marker. Furthermore NY-BR-1 positivity in apoeccrine glands of the axilla and anogenital region suggests a potential histogenetic link between these structures and Paget's disease.

The peripheral nervous system and the pathogenesis of prion diseases

Prion diseases are inevitably fatal neurodegenerative conditions which affect humans and a wide variety of animals. Unlike other protein aggregation diseases such as Alzheimer's, Parkinson's, and polyglutamine repeat diseases, prion diseases are unique in that they are transmissible. Therefore, prion diseases are also called transmissible spongiform encephalopathies. A number of prion diseases are caused by peripheral uptake of the infectious agent. In order to reach their target, the central nervous system, prions enter their host, accumulate and replicate in lymphoid organs, and eventually spread to the central nervous system via peripheral nerves. Once the agent has reached the central nervous system, disease progression is rapid, resulting in neurodegeneration and death. In this article, we review the state of knowledge on the routes of neuroinvasion used by the infectious agent in order to gain access to the central nervous system upon entry into extracerebral sites.

Variant Creutzfeldt–Jakob disease: between lymphoid organs and brain

Prion diseases are often caused by peripheral uptake of the infectious agent. To reach their ultimate target, the central nervous system (CNS), prions enter their host, replicate in lymphoid organs and spread via peripheral nerves. Once the agent has reached the CNS disease progression is rapid, resulting in neurodegeneration and death. many of these mechanisms have been uncovered using genetically modified mice. A recently published study demonstrated the presence of pathological prion protein in sympathetic ganglia of patients suffering from variant Creutzfeldt-Jakob disease, suggesting that these mechanisms might apply to humans.

In vitro activity of oral antimicrobial agents against clinical isolates of Pasteurella multocida

Pasteurella multocida causes a wide variety of infections and is the most common localized soft tissue infection after animal bite injuries. Penicillin or amoxicillin has been considered agent of choice for therapy. Reported beta-lactamase production by some isolates, the therapeutic dilemma of the penicillin allergic patient, and the polymicrobial nature of some infections led to this study of alternate antimicrobial agents. The in vitro activity of ampicillin, amoxicillin/clavulanate, cefprozil, cefuroxime, erythromycin, clarithromycin, trimethoprim/sulfamethoxazole, ciprofloxacin, and tetracycline were compared to penicillin against 73 geographically diverse isolates of P. multocida from human infections collected since 1991. MIC90 (microgram/mL) were as follows: penicillin < or = 0.06; ampicillin < or = 0.5; amoxicillin/clavulanate < or = 0.5; cefaclor 1.0; cefprozil 1.0; cefpodoxime 0.06; cephalothin 2.5; cefuroxime < or = 0.25; erythromycin 2.0; azithromycin 1.0; clarithromycin 4.0; trimethoprim/sulfamethoxazole < or = 0.5/9.5; ciprofloxacin < or 0.25; tetracycline < or = 2.0. No beta-lactamase producing isolates were found in this study. This in vitro study has identified alternate oral agents to penicillins that may be appropriate for therapy of P. multocida infections.

Comparison of five different susceptibility test methods for detecting antimicrobial agent resistance among Haemophilus influenzae isolates

The detection of antimicrobial agent resistance among ninety-eight Haemophilus influenzae isolates was assessed by six different antibiotic test methods: agar dilution on Mueller-Hinton agar supplemented with 5% lysed horse blood (MH-LHB), E-test using both Haemophilus test medium (HTM) agar and chocolate Mueller-Hinton (CMH) agar plates, Vitek Haemophilus susceptibility cards, and three overnight microdilution systems that included two commercial systems, Micro-Media and MicroScan, and the reference broth microdilution method using HTM broth. Agents tested in the study included ampicillin, amoxicillin/clavulanic acid (A/C), cefaclor, cefuroxime, cefotaxime, ceftriaxone, chloramphenicol, and trimethoprim/sulfamethoxazole. Both the reference HTM microbroth dilution method and agar dilution correctly classified all nine of the beta-lactamase negative ampicillin resistant (BLNAR) isolates. Each of the other test methods failed to detect one of the BLNAR strains, either because of growth failure (Micro-Media and MicroScan) or miscategorization of an isolate as susceptible (E-Test HTM, E-Test CMH, and Vitek). None of the test methods detected all six isolates identified as A/C resistant by HTM microbroth dilution. Of the remaining antimicrobials tested, ampicillin and cefuroxime yielded data that could be compared by all test methods. The very major, major, and minor errors for these two antimicrobials in comparison to the reference HTM microdilution method were as follows: Micro-Media (1.7%, 0%, and 4.8%); MicroScan (11.9%, 0%, and 8.1%); E-Test HTM (1.6%, 0%, and 2.0%); E-Test CMH (1.6%, 1.6%, and 4.6%); Vitek (8.1%, 0%, and 3.1%); and agar dilution on MH-LHB (0%, 0%, and 4.6%). Micro-Media and MicroScan panels failed to support the growth of 4.1% and 5.1% of the isolates, respectively.

Evaluation of Amplicor PCR for direct detection of Mycobacterium tuberculosis from sputum specimens

We evaluated the Amplicor PCR assay (Roche Molecular Systems, Branchburg, N.J.) for direct detection of Mycobacterium tuberculosis in sputum. A total of 532 specimens from 270 patients were decontaminated and stored at 4 or -75 degrees C until assayed by PCR. This assay used three-step sample preparation, biotinylated primer pairs, AmpErase, and a microtiter format for amplicon capture and detection. Amplicor PCR results were compared with clinical history, culture from a Lowenstein-Jensen slant, and results from the BACTEC TB-460 system. Eighty-seven cultures from 15 patients grew M. tuberculosis; of these, 83 (95%) were positive with the Amplicor PCR test. The false negatives were most likely due to sample variation and inhibitors. Of the 445 specimens from which M. tuberculosis was not isolated, 428 (96%) were negative with the Amplicor PCR test. Of the 17 M. tuberculosis culture-negative, Amplicor-positive specimens, 15 were reclassified as true positives because previous cultures grew M. tuberculosis. Of the 445 specimens which did not grow M. tuberculosis, Mycobacterium spp. other than M. tuberculosis were isolated from 150 specimens. Three of these 150 specimens were Amplicor positive; two were from a patient with a history of tuberculosis, and one specimen gave a false-positive result. We do not feel that this represents cross-reactivity, because repeated Amplicor testing of the isolate gave negative results. The microtiter plate has 96 wells. Allowing for six controls, 90 decontaminated specimens can be tested by one technologist in 7.5 h. This PCR assay took 7.5 h to complete and is a sensitive and specific, rapid method for the direct detection of M. tuberculosis from sputum.

Clinical comparison of the Baxter MicroScan Yeast Identification Panel and the Vitek Yeast Biochemical Card

To determine the reliability of the Baxter MicroScan Yeast Identification Panel, processed by the Walkaway-96, and the Vitek Yeast Biochemical Card, 150 clinical yeast isolates (30 Candida albicans, 67 Candida species, not albicans, 26 Torulopsis glabrata, 13 Cryptococcus neoformans, 4 Saccharomyces cerevisiae, 6 Trichosporon beigelii, 3 Rhodotorula species, and 1 Geotrichum species) were tested on both systems. Results were compared with those obtained by the API 20C and the appearance of yeast cells on cornmeal Tween-80 agar. After inoculation of each system, results were available in 4 hours with MicroScan panels, 24-48 hours with Vitek cards, and 72 hours with the API 20C strips. On initial testing, 101 (67%) and 128 (85%) isolates, respectively, were correctly identified by MicroScan and Vitek. After repeat testing, the number of correctly identified isolates increased to 123 (82%) by MicroScan and to 142 (95%) by Vitek. Yeasts most commonly misidentified were Candida tropicalis, T glabrata, and Candida parapsilosis by MicroScan and C tropicalis and T glabrata by Vitek.

Comparison of susceptibility test methods to detect penicillin-resistant Streptococcus pneumoniae

The detection of penicillin-resistant Streptococcus pneumoniae was assessed by six different methods: agar dilution, oxacillin screen by disk diffusion, E-test, and three overnight microdilution test methods that included commercial panels from MicroScan and Micro Media and in-house-made conventional panels using a commercial Haemophilus test medium (HTM) broth. Of the 52 pneumococcal isolates tested, 12 were resistant, 16 were relatively resistant, and 24 were susceptible to penicillin as defined by the reference agar dilution method. The oxacillin screen detected as resistant all 28 resistant and relatively resistant strains. The percentage of penicillin-resistant isolates detected by each minimum inhibitory concentration (MIC) test method was as follows: E-test (100%), Micro Media (75%), MicroScan (0%), and HTM (0%). With the relatively resistant isolates, the detection percentage was as follows: E-test (88%), Micro Media (94%), MicroScan (69%), and HTM (69%). In conclusion, the E-test and Micro Media MIC tests are acceptable confirmatory tests for detecting penicillin resistance among S. pneumoniae isolates.

Group A beta-hemolytic streptococcal bacteremia and intravenous substance abuse. A growing clinical problem?

Over an 18-month period, the incidence of group A beta-hemolytic streptococcal bacteremia rose from an average of 2.5 per 10,000 patient discharges to 17.9. A retrospective analysis was performed comparing patients with group A beta-hemolytic streptococcal bacteremia during this 18-month period with those who presented over the preceding 36 months. Most of the increased incidence was attributable to individuals hospitalized with a diagnosis of drug addiction who had concomitant soft-tissue infection, although the absolute number of hospitalized drug addicts did not change during this interval. No common or distinctive group A streptococcal serotypic patterns were discovered. This experience suggests that group A beta-hemolytic streptococcal bacteremia and soft-tissue infection may present in epidemic fashion among parenteral drug addicts in the absence of a common source.

Comparison of the API Staph-Ident and DMS Staph-Trac systems with conventional methods used for the identification of coagulase-negative staphylococci

Two commercial kit systems, the API Staph-Ident system (Analytab Products, Inc., Plainview, N.Y.) and the DMS Staph-Trac system (DMS Laboratories, Inc., Flemington, N.J.), were compared with conventional methods for the identification of nine species of coagulase-negative staphylococci. The API Staph-Ident system, a biochemical and chromogenic substrate micromethod, correctly identified 95 of 120 (79.2%) clinical isolates of coagulase-negative staphylococci after 5 h of incubation. The DMS Staph-Trac system, a miniaturized biochemical test system which requires a 24-h incubation period, correctly identified 106 (88.3%) of the same isolates. Both commercial systems were similar in cost and amount of technologist time required to inoculate and read each system. The clinical value of routine species identification of coagulase-negative staphylococci has not yet been established. The decision by clinical laboratories of whether to adopt this practice will be greatly facilitated by the availability of commercial kit systems which are both rapid and accurate.

Mechanism of action of Clostridium perfringens enterotoxin. Effects on membrane permeability and amino acid transport in primary cultures of adult rat hepatocytes

Purified enterotoxin from the bacterium Clostridium perfringens rapidly decreased the hormonally induced uptake of alpha-aminoisobutyric acid in primary cultures of adult rat hepatocytes. At 5 min after toxin addition the decrease in alpha-aminoisobutyric acid uptake appeared not due to increased passive permeation (estimated with L-glucose) or to increased alpha-aminoisobutyric acid efflux. When short uptake assay times were employed a depression of alpha-aminoisobutyric acid influx was observed in toxin-treated hepatocytes. The depression of alpha-aminoisobutyric acid influx was correlated with a rapid increase in intracellular Na+ (estimated using 22Na+) apparently effected by membrane damage. In contrast, the uptake of cycloleucine in the presence of unlabeled alpha-aminoisobutyric acid (assay for Na+-independent amino acid uptake) by hepatocytes treated with toxin for 5 min was decreased to only a small extent or not at all depending upon experimental design. At later times, C. perfringens enterotoxin increased the exodus of L-glucose, 3-O-methylglucose and alpha-aminoisobutyric acid from pre-loaded cells indicating that the toxin effects progressive membrane damage. When enterotoxin was removed by repeated washing after 5--20 min the decay of alpha-aminoisobutyric acid uptake ceased and appeared to undergo recovery towards the hormonally induced control level. The degree of recovery of alpha-aminoisobutyric acid uptake was inverse to the length of time of exposure to toxin. Adding at 10 min specific rabbit antiserum against C. perfringens enterotoxin without medium change also reversed the effect of toxin on increased intracellular 22Na+, and on the exodus (from preloaded cells) of alpha-aminoisobutyric acid, L-glucose, and 3-O-methylglucose.

Response of mouse liver glycogen cycle enzymes to endotoxin treatment

The present study was undertaken to characterize endotoxin-induced changes in carbohydrate metabolism and more specifically, to determine the contribution of glycogenolysis to the loss of liver glycogen. Female ICR mice, fasted overnight, were injected with a median lethal dose (LD50, 9 mg/kg) of endotoxin extracted from Salmonella typhimurium strain SR-11. Glycogen synthase and glycogen phosphorylase activities were measured at 0.5 and 6 h after treatment. Endotoxin treatment did not alter total glycogen synthase activity, but the amount of enzyme present in the active form was significantly lower in endotoxic mice. There was no significant increase in glycogen phosphorylase activity in endotoxin-treated mice. Glycogen phosphorylase was activated to the same extent in control and endotoxic mice by decapitation or intravenous epinephrine (25 or 1 mug/kg). The results of this study indicate no significant increase in glycogen phosphorylase activity in endotoxic mice, contraindicating enhanced glycogenolysis as a mechanism for depletion of carbohydrate following endotoxin injection. Altered activation of glycogen synthase, however, may contribute to the loss of glycogen during endotoxemia.