Clinical application of targeted next-generation sequencing for colorectal cancer patients: a multicentric Belgian experience

International guidelines made RAS (KRAS and NRAS) status a prerequisite for the use of anti-EGFR agents for metastatic colorectal cancer (CRC) patients. Daily, new data emerges on the theranostic and prognostic role of molecular biomarkers; this is a strong incentive for a validated, sensitive, and broadly available molecular screening test. Next-generation sequencing (NGS) has begun to supplant other technologies for genomic profiling. We report here our 2 years of clinical practice using NGS results to guide therapeutic decisions.

The Ion Torrent AmpliSeq colon/lung cancer panel, which allows mutation detection in 22 cancer-related genes, was prospectively used in clinical practice (BELAC ISO 15189 accredited method). The DNA of 741 formalin-fixed paraffin-embedded CRC tissues, including primary tumors and metastasis, was obtained from 14 different Belgian institutions and subjected to targeted NGS.

Of the tumors tested, 98% (727) were successfully sequenced and 89% (650) harbored at least one mutation. KRAS, BRAF and NRAS mutations were found in 335 (46%), 78 (11%) and 32 (4%) samples, respectively. These mutation frequencies were consistent with those reported in public databases. Moreover, mutations and amplifications in potentially actionable genes were identified in 464 samples (64%), including mutations in PIK3CA (14%), ERBB2 (0.4%), AKT1 (0.6%), and MAP2K1 (0.1%), as well as amplifications of ERBB2 (0.3%) and EGFR (0.3%). The median turnaround time between reception of the sample in the laboratory and report release was 8 calendar days.

Overall, the AmpliSeq colon/lung cancer panel was successfully applied in daily practice and provided reliable clinically relevant information for CRC patients.

IL-10 in vivo gene expression in a cell-induced animal model of proliferative vitreoretinopathy

Due to inhibitory activities on cell-mediated immune responses, interleukin-10 (IL-10) has been proposed as a good candidate to treat inflammatory eye disease and proliferative vitreoretinopathy (PVR). In this study we evaluate the effect of human IL-10 (hIL-10) expression in a cell-induced animal model of PVR. Rabbit dermal fibroblasts were genetically modified by infection with retroviral particles carrying the neomycin resistance gene (neoR) alone or in combination with the hIL-10 gene. PVR was induced in rabbits by intravitreal injections of RDF hIL-10 or RDF neo. Some rabbits received instead injections of soluble recombinant hIL-10 (rhIL-10). PVR was graded by fundoscopy. Eyes were enucleated for histology at day 28. ELISA was performed to measure hIL-10 production in RDF supernatants and in vitreous samples, 24 h after injection. Results showed that in vitro hIL-10 production by RDF was 24,500 pg/10(6) cells/ml/24 h. In vivo IL-10 secretion was detected in all rabbits injected with RDF hIL-10 but was undetectable in control rabbits. Similar clinical grades of PVR were found in rabbits injected with RDF hIL-10 or RDF neo. Histology showed that all eyes injected with RDF hIL-10 had significant inflammatory infiltration whereas only one control eye was clearly inflamed. Rabbits injected with soluble rhIL-10 had normal fundoscopy and normal histology. In conclusion, our results show that in vivo, in a cell-induced model of PVR, hIL-10 has no effect in the clinical progression of PVR. Histology, however, shows that pro-inflammatory effects seem to overcome its suppressive properties.

Diffuse large B-cell lymphoma with fibrillary matrix

Diffuse large B-cell lymphoma (DLBCL) with fibrillary matrix is an extremely rare variant of non-Hodgkin's lymphoma (NHL) whose pathological features are poorly known. Here, we report on our experience with such a condition arising in a 71-yr-old woman. Our findings not only demonstrate that DLBCL with fibrillary matrix actually represents a peculiar subtype of DLBCL, but they also illustrate that the cytologic and flow cytometric features in this disorder can be deceptive enough as to mislead even the most experienced cytopathologist.

Heterotopic gastric mucosa in the upper esophagus: a prospective study of 33 cases and review of literature

BACKGROUND AND STUDY AIMS

The prevalence of endoscopically diagnosed heterotopic gastric mucosa in the upper esophagus (HGMUE) has been reported in a few studies, and varies from 0.1 to 10%. Clinical relevance and possible association with other pathological conditions remain a matter of debate. A prospective study was carried out to determine the prevalence of HGMUE, the influence on it of age and sex, and to study the macroscopic and microscopic aspects of the lesion, its clinical relevance and possible association with other pathological conditions.

PATIENTS AND METHODS

A total of 674 new patients with upper digestive complaints or alteration of their state of health underwent upper gastrointestinal endoscopy, with special attention paid to the proximal esophagus when withdrawing the gastroscope. They had been carefully questioned, especially regarding possible complaints, which could have drawn attention to the upper esophagus.

RESULTS

Heterotopic columnar epithelium in the proximal esophagus was found in 4.9 % of patients. No difference was observed according to age or sex. A mild to moderate chronic inflammatory infiltration of the heterotopic patch was observed in most cases, not related to the presence in the lesion of Helicobacter pylori, which was found in only one case. Pathological conditions of the gastroesophageal junction, especially esophagitis, were slightly more frequent in patients with HGMUE. Mild complaints, possibly related to the presence of the lesion, were observed in three out of the 33 cases.

CONCLUSIONS

On the basis of our prospective study we consider that heterotopic columnar epithelium in the proximal esophagus is a rather common, generally asymptomatic, benign congenital anomaly. Malignant transformation of heterotopic gastric mucosa in the upper esophagus and other severe complications are rare. The need for surveillance should be reserved for the rare cases with metaplasia or dysplasia in the heterotopic columnar mucosa.

Anaplastic large cell lymphoma of true histiocytic origin in an infant: unusual clinical, hematological, and cytogenetic features

We report here the case of a 7-month-old boy who developed anaplastic large cell lymphoma of true histiocytic origin or malignant histiocytosis, with fever, bone and bone marrow infiltration. Usual clinical features were absent. The neoplastic nature of the disease was supported by the presence of clonal chromosomal abnormalities [t(6;8)(p23;p21),der(8)del(8)(q11aq13), der(22) t(11;22) (q13;13)]. Neither B nor T lineage could be demonstrated here. Morphology, ultrastructural analysis, surface antigens expression, and cytogenetics were more specific for the monocyte-macrophage lineage.

Progressive paraparesis due to thoracic extramedullary hematopoiesis in myelofibrosis. Case report

A patient with myelofibrosis who developed a progressive paraparesis caused by spinal cord compression due to thoracic extramedullary hematopoietic tissue is reported. He recovered well after local radiotherapy alone.

Leukemia and lymphoma immunophenotyping in cell smears with immunogold-silver staining

The potential of the immunogold-silver staining (IGSS) technique for immunophenotyping leukemia and lymphoma cells in cell smears was examined. Peripheral blood, bone marrow aspirates, lymph node biopsy specimens, fine-needle aspirates, and biologic fluids of 83 patients with acute or chronic leukemias, non-Hodgkin's lymphomas, or Hodgkin's disease were labeled. Cell smears, cytocentrifuge preparations, or imprints were fixed, incubated with the reagents, and counterstained with May-Grünwald-Giemsa. Stable immunostaining and good morphologic characteristics allowed accurate cell identification and rapid enumeration of the positive cells. The immunophenotypes obtained with the use of 35 monoclonal antibodies with different specificities were similar to those determined by flow cytometry or immunohistochemical studies on the same samples. This IGSS method was especially useful for the examination of poor samples or complex cell suspensions with rare malignant cells. It could be an alternative to the immunoenzyme methods that generally are used for this purpose.

Southern blot analysis in a case of Richter's syndrome. Evidence for a postrearrangement heavy chain gene deletion associated with the altered phenotype

Richter's syndrome (RS) can be defined as the emergence of an aggressive lymphoma in patients suffering from chronic lymphocytic leukemia (CLL). The authors performed immunophenotypic and Southern blot analysis of the peripheral blood and tissue specimen of a patient with RS. Using immunoperoxidase and immunogold-silver staining techniques and a panel of monoclonal antibodies, the authors found that the large cells characteristic of RS showed an altered immunophenotype as compared with the CLL cells and did not express mu heavy chain. Southern blot analysis revealed identical kappa light chain rearrangements in both tumoral cell populations consistent with a common clonal origin. Using the JH probe and several restriction enzymes, the authors also found evidence for a postrearrangement deletion of the heavy chain mu gene. These findings suggest that in this case of RS, a deletion of the heavy chain mu gene resulted in loss of mu expression by the larger cells that were characteristic of RS and was associated with their altered phenotype.

Metastasizing neuroendocrine carcinoma of the larynx with calcitonin and somatostatin secretion and CEA production, resembling medullary thyroid carcinoma

A 55-year-old man presented with a metastasizing moderately differentiated neuroendocrine carcinoma of the larynx (atypical carcinoid). Immunocytochemical demonstration of neuroendocrine markers (neuron-specific enolase and chromogranin-A) and presence of membrane-bound neurosecretory granules in the cells established the neuroendocrine nature of the tumour. In addition, the tumour was found to produce calcitonin, somatostatin and carcino-embryonic antigen (CEA). Calcitonin and somatostatin were also secreted. On the basis of this particular marker constellation the tumour closely resembles medullary thyroid carcinoma. Review of the recent literature on carcinoids of the larynx reveals immunoreactivity for calcitonin and CEA in a high percentage of cases.

Diagnostic and prognostic value of the MB2 monoclonal antibody in paraffin-embedded bone marrow sections of patients with multiple myeloma and monoclonal gammopathy of undetermined significance

Routinely processed bone marrow biopsies of 59 patients with untreated multiple myeloma (MM) and of 41 patients with monoclonal gammopathies of undetermined significance (MGUS) were immunocytochemically studied with the MB2 monoclonal antibody. In 54 of 59 biopsies of patients with MM, most neoplastic plasma cells showed strong cytoplasmic positivity to MB2. In contrast, only three biopsies of patients with MGUS contained highly MB2-positive plasma cells, whereas the plasma cells in the remaining biopsies were either negative (18 of 41) or revealed a weak dot-like staining of the cytoplasm (20 of 41). Plasma cells in tonsillar tissue, gastric and duodenal mucosae, and bone marrow with reactive plasmacytosis were not stained with MB2. These findings suggest that MB2 helps to distinguish between MM and MGUS. Because the five MB2-negative patients with MM were all in stage III and had very short survival time, neoplastic plasma cell staining with MB2 could also have a prognostic significance.

Anaplastic small cell (oat cell) carcinoma of the tonsils: report of two cases

Two cases of anaplastic small cell (oat cell) carcinoma of the tonsils are presented. In the first, cervical metastases preceded the manifestation of the primary tumour by 2 years. In case 2 the tonsillar carcinoma was accompanied by a bronchial tumour of the same histological type and by cervical and axillary metastases. Positive Grimelius stain, positive immunohistochemical staining for chromogranin A and neurone-specific enolase and the presence, in case 1, of membrane-bound granules indicate that these tumours display many similarities with neuroendocrine carcinomas even if they originate from pluripotential ductal cells of tonsillar minor salivary glands and not from Kulchitsky-like cells.

Endometrial morphology in stimulated in vitro fertilization cycles and after steroid replacement therapy in cases of primary ovarian failure

Endometrial morphology and ultrastructure are studied in 17 spontaneous, 23 stimulated, and 18 artificial cycles in cases of primary ovarian failure. Normal light-microscopic aspect was found, but impaired development of nucleolar channel system and stronger intercellular junction have been observed by electron-microscopic studies in stimulated cycles with relative excess of luteal estrogen. Normal glandular maturation can be obtained in patients with premature menopause, given adequate steroid replacement, but an abnormally dense fibrocytic aspect of the stroma is characteristic of the first treatment cycles.

Detection of cell surface antigens in cryostat sections with immunogold-silver staining

Immunogold-silver staining was used for the detection of lymphocyte cell surface antigens in cryostat sections of lymphoid tissues. The sections were incubated with monoclonal mouse antibodies and then with colloidal gold-labeled goat anti-mouse antibodies. They were then immersed in a physical developer, counterstained, and mounted. In light microscopy, the tissue architecture was well preserved, and a dark labeling was seen on the positive cells. Optimal labeling conditions were determined. The distribution of the lymphocyte subsets, as defined by a panel of monoclonal antibodies in tonsil and reactive lymph nodes, was similar to that found with a biotin-avidin-horseradish peroxidase method. The monoclonality of the neoplastic cells in lymph nodes of B-cell non-Hodgkin's lymphomas clearly could be demonstrated. The sensitivity of the technic was comparable with that of the biotin-avidin-horseradish peroxidase labeling method. In addition, immunogold-silver labeling was combined with acid phosphatase cytochemistry.

Unusual nonimmunoglobulin-containing inclusions in a case of follicular large cell lymphoma

Intracytoplasmic inclusion bodies were found in a case of follicular large cell lymphoma. They did not react with anti-immunoglobulin antisera and showed no enzyme reactivity. On electron microscopy the inclusions consisted of loosely packed fibrillar material not surrounded by a membrane or by rough endoplasmic reticulum. They were found only in the large lymphomatous cells. Immunocytochemistry showed a reactivity of these cells with anti-HLA-Dr and the OKT10 monoclonal antibodies. The nature of the inclusions remains unknown. They differ significantly from those described in the literature in cases of B-cell lymphoproliferative disorders.

Increased prostate-type acid phosphatase activity in serum and typical bone lesions simulating the presence of prostatic carcinoma

In a man with myelomonocytic leukemia, the association of increased prostatic acid phosphatase activity in serum and the presence of typical bone lesions on roentgenography suggested the existence of disseminated prostatic carcinoma. During the clinical observation period, however, prostatic involvement could not be proved. Moreover, bone pain and prostatic-type acid phosphatase activity in serum closely paralleled monocyte counts and the degree of hepatosplenomegaly and leukemic skin lesions. Finally, meticulous postmortem examination of the prostate showed no prostatic carcinoma. This clinical picture appears to be entirely explicable in terms of leukemic organ infiltration and the proliferation of monocytes, which are known to contain acid phosphatase isoenzymes like those in the prostate.

Increased prostate-type acid phosphatase activity in serum and typical bone lesions simulating the presence of prostatic carcinoma

In a man with myelomonocytic leukemia, the association of increased prostatic acid phosphatase activity in serum and the presence of typical bone lesions on roentgenography suggested the existence of disseminated prostatic carcinoma. During the clinical observation period, however, prostatic involvement could not be proved. Moreover, bone pain and prostatic-type acid phosphatase activity in serum closely paralleled monocyte counts and the degree of hepatosplenomegaly and leukemic skin lesions. Finally, meticulous postmortem examination of the prostate showed no prostatic carcinoma. This clinical picture appears to be entirely explicable in terms of leukemic organ infiltration and the proliferation of monocytes, which are known to contain acid phosphatase isoenzymes like those in the prostate.

Two monoclonal antibodies (OKIa1 and OKT10) for the study of the final B cell maturation

OKT10 is a monoclonal antibody which recognizes an antigenic structure of 45,000 daltons which is present on precursor T and B cells, activated T cells and some monocytes. In this study, this antibody was shown to react strongly with the surface membrane of plasma cells. In addition, OKT10 can be used to study final B cell maturation since the OKT10 antigen is expressed on mature lymphocytes and lymphoplasmacytic cells. Acquisition of OKT10 reactivity occurs in an inverse or opposite relationship to the presence of Ia-like antigenic expression. Therefore, these two antigens can be employed as complementary opposite reactants for the study of mature B cell malignancies, such as CLL, multiple myeloma, and Waldenström malignancy.