Constantine S. Papadimitriou

Epithelial HLA-DR expression and lymphocyte subsets in gastric mucosa in type B chronic gastritis

Lymphocyte subpopulations (B, T4, T8), monocytes/macrophages (LeuM5, KiM5) and HLA-DR antigen expression were studied immunohistochemically in frozen sections from 32 antral and 37 fundal biopsies of type-B chronic gastritis. Aberrant HLA-DR antigen expression in epithelial cells of gastric mucosa was found in all cases closely related to mononuclear infiltrates. Epithelial HLA-DR expression and mononuclear infiltrates were practically absent in foci of intestinal metaplasia. These findings suggest that an immunopathologic mechanism probably plays a role in initiation or perpetuation of type-B chronic gastritis.

Chemopreventive activity of very low dose dietary tannic acid administration in hepatoma bearing C3H male mice

Tannins are plant polyphenols comprising a heterogeneous group of compounds. Tannic acid is a common tannin found in tea, coffee, immature fruits, etc. and it has also been used as a food additive. An increasing body of experimental evidence supports the hypothesis that tannins exert anticarcinogenic activity in chemically induced cancers in animal models. In the present study, tannic acid was administered in very low doses in the drinking water of C3H male mice divided into three groups (75 mg/l, 150 mg/l and 300 mg/l). These animals carry a genetic defect and show a high incidence of spontaneous liver tumors (> 50%) at an age older than 12 months. The results showed a decrease in the overall incidence of hepatic neoplasms (adenomas plus carcinomas): 53.3% of animals in the control group developed hepatic neoplasms versus 33.3% in the group given a low dose of tannic acid, 26.6% in the group given a medium dose and 13.3% in the high dosage group. The difference was more pronounced in the animals with carcinomas: 4.44% of mice who received tannic acid developed carcinomas versus 33.3% of those in the control group. Tannic acid administration did not affect the PCNA labeling index of normal hepatocytes. It is concluded that tannic acid dietary intake in low doses can exert a strong dose-dependent chemoprotective activity against spontaneous hepatic neoplasm development in C3H male mice, most probably through antipromoting mechanisms.

Immunohistochemical Detection of the c-myc Oncogene Product in Normal, Hyperplastic and Carcinomatous Endometrium

The expression and the distribution of the c-myc oncogene product (p62) was studied by a 3-step immunoperoxidase technique using the monoclonal antibody myc 1-6 E10 in 22 cases of normal endometrium (11 proliferative and 11 secretory phase), 43 endometrial hyperplasias (24 adenomatous and 19 adenocystic) and 26 endometrial carcinomas. Increased expression of c-myc product appeared in endometrial carcinomas compared with respective non-neoplastic tissue (p < 0.001). The immunolocalization of the c-myc protein shows a consistent difference between the various histologic patterns of non-neoplastic and neoplastic endometrium. Nuclear staining of the c-myc product was demonstrated in epithelial cells of the proliferative phase and predominantly in poorly differentiated forms of endometrial carcinomas. On the other hand cytoplasmic staining was found predominantly in the secretory phase and in well differentiated carcinomatous endometrium. In hyperplastic endometrium an intermediate immunohistochemical pattern was observed. The results of the present study emphasize that c-myc product overexpression and localization plays an important role in initiation, differentiation and progression of endometrial carcinomas.

Cyclin D1 overexpression in multiple myeloma. A morphologic, immunohistochemical, and in situ hybridization study of 71 paraffin-embedded bone marrow biopsy specimens.

Cyclin D1 expression was evaluated by immunohistochemical analysis and biotin-labeled in situ hybridization (ISH) in a series of 71 decalcified, paraffin-embedded bone marrow biopsy specimens from patients with multiple myeloma (MM). Cyclin D1 messenger RNA (mRNA) overexpression was detected by ISH in 23 (32%) of 71 cases, whereas cyclin D1 protein was identified by immunohistochemical analysis in 17 (24%) of 71 specimens. All cases that were positive by immunohistochemical analysis also were positive by ISH. Statistically significant associations were found between cyclin D1 overexpression and grade of plasma cell differentiation and between cyclin D1 overexpression and extent of bone marrow infiltration. Our findings demonstrate the following: (1) ISH for cyclin D1 mRNA is a sensitive method for the evaluation of cyclin D1 overexpression in paraffin-embedded bone marrow biopsy specimens with MM. (2) ISH is more sensitive than immunohistochemical analysis in the assessment of cyclin D1 expression. (3) Cyclin D1 overexpression in MM is correlated positively with higher histologic grade and stage.

Progenitor cell activation in chronic viralhepatitis

Abstract: Background/Aim: Oval cell proliferation is known to occur in experimental models of hepatic regeneration and carcinogenesis. Recent studies have suggested that activation of progenitor cells, representing the human counterpart of oval cells, may play a role in hepatic diseases. Therefore, we evaluated putative progenitor cells in chronic viral hepatitis.

Primary gastrointestinal malignant lymphomas. A morphologic and immunohistochemical study.

Thirty‐nine primary gastric and 22 intestinal malignant lymphomas collected from 1969 to 1980 have been studied morphologically and immunohistochemically. Eighteen of the 61 gastrointestinal lymphomas were of low‐grade malignancy (9 lymphoplasmacytoid/cytic, 3 centrocytic, 6 centroblastic/centrocytic) and 43 were of high‐grade malignancy (14 centroblastic, 7 lymphohlastic, 22 immunoblastic malignant lymphomas) according to the Kiel classification. The peroxidase‐antiperoxidase (PAP) method was used in 53 of the 61 cases. Twenty‐seven of them revealed a monoclonal positivity for intracytoplasmic IgS: kappa light chains in 18 and lambda light chains in 7 cases. Two cases represented alpha chain disease, revealing only a heavy chain positivity. The most frequent staining pattern of the lymphoma cells was that of kappa/mu. Cells with a mixed centrocytic and plasma cell configuration (centrocytoid plasma cells) proved to be positive for intracytoplasmic IgS. Lymphoma cells of all tested cases proved to be negative for all histiocytic markers. Histologically and immunohistochemically, the Greek cases of primary gastrointestinal malignant lymphomas seem to resemble “western” type lymphomas.

The canals of hering might represent a target of methotrexate hepatic toxicity.

Methotrexate treatment for psoriasis is known to cause hepatic fibrosis in some patients, which might progress to cirrhosis. The fine, radiating, fibrous septa developing in this setting have a distribution that is reminiscent of the location of the canals of Hering (coH). To assess the possibility of fibrous obliteration of the coH in patients receiving methotrexate, we developed a staining technique by combining an immunohistochemical stain for cytokeratin 7 with a modified Masson trichrome. Sixteen biopsy specimens from 7 patients were evaluated. The biopsies had a variety of histologic changes, including steatosis, anisonucleosis, multinucleation, chronic inflammation, bile duct damage, and ductular reaction. Fibrosis was present in 13 biopsy specimens (81%) and was mild in 7, moderate in 3, and severe in 3 specimens. Compared with normal (control) liver specimens, biopsy specimensfrom patients receiving methotrexate had decreased numbers of coH (1.9 +/- 0.8 vs 5.2 +/- 1.7; P < .025). In specimens with moderate or severe fibrosis, fibrous septa sometimes extended along the coH. These findings suggest that scarring of the coH might be a consequence of the toxic effects of methotrexate.

In Situ Hybridization and Reverse Transcription–Polymerase Chain Reaction for Cyclin D1 mRNA in the Diagnosis of Mantle Cell Lymphoma in Paraffin-Embedded Tissues

Mantle cell lymphoma (MCL) is characterized by the chromosomal translocation t(11;14), which involves rearrangement of the bcl-1 proto-oncogene to the immunoglobulin heavy chain gene and results in overexpression of cyclin D1 mRNA. In this study, we evaluated the diagnostic relevance of three methods that may be helpful in the diagnosis of MCL: in situ hybridization (ISH) and a stringent reverse transcriptase–polymerase chain reaction (RT-PCR) protocol for cyclin D1 mRNA, and immunohistochemistry for cyclin D1 protein. The study group included 37 paraffin-embedded specimens (25 from lymph nodes and 12 from extranodal tissues) from 30 patients. MCL diagnosis was performed according to the Revised European-American Classification of Lymphoid Neoplasms. Twenty-nine patients with non-MCL lymphoproliferative disorders comprised the control group. Biotin-labeled ISH was performed in 28 cases of MCL, 24 (86%) of which were found to be positive. As shown by ISH in extranodal tissues, cyclin D1 mRNA was present not only in neoplastic lymphoid cells, but in other cell types as well. For this reason, RT-PCR results were considered reliable for MCL diagnosis only on informative material (from tissues that do not normally express cyclin D1); this method was evaluated as positive in 16 of 18 (89%) MCL cases. Cyclin D1 immunopositivity was present in 20 of 29 (69%) MCL cases. No members of the control group were found to express cyclin D1 mRNA by either ISH or RT-PCR under the stringent conditions used. In conclusion, stringent RT-PCR for cyclin D1 expression can be helpful in MCL diagnosis in paraffin-embedded material from lymph nodes. ISH is a sensitive method for cyclin D1 mRNA detection; its sensitivity is superior to that of cyclin D1 immunohistochemistry and similar to that of the stringent RT-PCR used. ISH is very specific as well, clearly more specific than RT-PCR, because it allows the correlation of molecular findings with morphology. This method can be applied on all types of paraffin-embedded tissues and provides an accurate tool for MCL diagnosis.

Mismatch Repair Gene Expression in Malignant Lymphoproliferative Disorders of B-cell Origin

We investigated mismatch repair (MMR) gene expression in 31 lymphoid tissue specimens and bone marrow aspirates with malignant lymphoproliferative disorders of B-cell origin (25 cases of lymphoma and six cases of plasma cell myeloma). A multiplex RT-PCR assay was employed to assess the relative expression of the hMSH2, hMLH1 and hPMS1 genes, as compared to β -actin, which was used as an internal control of gene expression. MSH2 was further evaluated at the protein level by immunohistochemistry. The findings were compared to those of a control group of lymphoid tissue specimens without evidence of malignancy (n =6). Changes in MMR gene expression were observed in 10 out of 31 cases of the study group (32%). All three MMR gene transcripts were low in two out of six plasma cell myelomas, which had extensive bone marrow infiltration by neoplastic cells. The hMSH2 transcript was present in all cases of lymphoma, while the expression of hMLH1 and hPMS1 was significantly low in some large B-cell lymphomas (four and five out of 14 cases, respectively) and in mantle cell lymphomas of the blastoid type (two out of two cases). No MMR gene aberrations were found in seven cases of B-cell lymphocytic leukemia and two cases of mantle cell lymphoma of centrocyte-like type. These findings demonstrate that the expression rates of the hMSH2, hMLH1 and hPMS1 genes differ among various types of B-cell lymphoproliferative disorders, and suggest that MMR gene expression may be related to the natural history of these neoplasms. This study identified a higher incidence of MMR gene aberrations in lymphoma types characterized by aggressive biologic behavior, as compared to neoplasms with a more indolent course.

Relative expression of human telomerase catalytic subunit (hTERT) transcripts in astrocytic gliomas

Human telomerase catalytic subunit (hTERT) expression has been reported as a marker for malignancy in various tumor systems. The aim of the present study was to investigate the relative expression of hTERT (relhTERT) and its transcripts A+B+ (contained in the full-length product), Adel and Bdel in astrocytic gliomas (grades I–IV, n=38). relhTERT was assessed by duplex reverse transcription-PCR and the expression profile of Adel, Bdel and A+B+ transcripts by nested real time-PCR. relhTERT and A+B+ presence correlated well with each other (P<0.001) and with histological grading [grades I–II (low) vs III–IV (high), PrelhTERT=0.002 and PA+B+<0.001]. A+B+ was detected in one out of seven hTERT-positive low-grade tumors, while it was present in 96.3%, and predominantly expressed in 59.3% of high-grade tumors. Bdel predominance was observed only in three cases, irrespective of grading, while Bdel levels equal or close to those of A+B+ were found in 30.4% of grade IV tumors. In situ hybridization with specific Bplus and Bdel probes revealed positive signals for both mRNAs in association with relhTERT and respective variant profiles. In addition, this method was useful in assessing hTERT expression in cases where sampling errors for RT-PCR were unavoidable. Our findings show that except for differences in relhTERT, low- and high-grade astrocytic gliomas exhibit distinct hTERT variant profiles, most of which seem to be in line with the role attributed to hTERT regarding its contribution to the acquisition of malignant potential during astrocyte carcinogenesis. Low-grade tumors mainly express Adel and Bdel. High-grade tumors, especially grade IV, always express A+B+, mostly but not always in predominance over Adel and Bdel. In this same group, profiles with Bdel predominance or relatively equal A+B+/Bdel expression are also observed, and Adel is often missing. Whether these differences characterize tumors with different biological behavior remains to be elucidated.