Antonio Palacín

VCAM-1 and ICAM-1 mediate leukocyte-endothelial cell adhesion in rat experimental colitis

BACKGROUND & AIMS The molecular mechanisms responsible for leukocyte recruitment in experimental colitis are poorly understood. The aims of this study were to measure expression of endothelial intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) and to determine their role in leukocyte recruitment in experimental colitis. METHODS Rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis and control rats were studied 1, 7, or 21 days after treatment. ICAM-1 and VCAM-1 expressions were measured by the double radiolabeled antibody technique. Leukocyte-endothelial cell interactions were determined in colonic venules by fluorescence intravital microscopy. Therapeutic effects of treatment with anti-VCAM-1 antibodies were also assessed. RESULTS Colonic endothelial ICAM-1 was constitutively expressed and did not increase in colitic animals. In contrast, constitutive expression of VCAM-1 was low but markedly increased (6-fold) 1 and 7 days after induction of colitis. Increased colonic expression of VCAM-1 paralleled macroscopic damage score, myeloperoxidase activity, and increased leukocyte adhesion in colonic venules. The latter was significantly decreased by immunoneutralization of ICAM-1 and completely abrogated by immunoneutralization of VCAM-1. Long-term administration of anti-VCAM-1 antibody resulted in significant attenuation of colitis. CONCLUSIONS Induction of colitis in rats by TNBS is followed by up-regulation of endothelial VCAM-1. VCAM-1 and constitutive ICAM-1 are major determinants of leukocyte recruitment to the inflamed intestine.

CD10 expression in epithelial tissues and tumors of the gynecologic tract: a useful marker in the diagnosis of mesonephric, trophoblastic, and clear cell tumors.

We tested 417 cases of formalin-fixed, paraffin-embedded normal or hyperplastic gynecologic tissues as well as neoplasms involving the gynecologic tract with a monoclonal antibody against CD10 (clone 56C6), with special emphasis on epithelial and epithelial-like structures and tumors. CD10 was always expressed in mesonephric remnants (mesonephric remnants of the uterine cervix, epoophoron, rete ovarii) and tumors (mesonephric adenocarcinoma of the uterine cervix, tumors of wolffian origin of the broad ligament and ovary). CD10 was also positive in the syncytiotrophoblast, cytotrophoblast, and intermediate trophoblast of normal gestations, partial and complete moles, choriocarcinoma, and placental site trophoblastic tumors. Finally, CD10 was positive in several metastatic neoplasms to the gynecologic tract (100% in metastatic renal clear cell and intestinal carcinomas and melanomas). In contrast, CD10 was almost invariably negative in müllerian epithelia of the female genital tract and in their corresponding tumors, with the exception of focal expression found in squamous epithelia and tumors with squamous differentiation. Thus, the expression of CD10 may be useful in the establishing the diagnosis of mesonephric and trophoblastic tumors and in the differential diagnosis between gynecologic clear cell carcinoma (always negative) and metastatic clear cell carcinoma of renal origin.

OVEREXPRESSION OF THE 67-kD LAMININ RECEPTOR CORRELATES WITH TUMOUR PROGRESSION IN HUMAN COLORECTAL CARCINOMA

The high affinity 67‐kD laminin receptor (67LR) is a cell surface protein whose expression is increased in a number of human carcinoma models. To date, 67LR expression in colorectal carcinomas has been examined in a small number of cases. 67LR expression has been immunohistochemically analysed in a large series of human colorectal neoplasms, using the MLuC5 monoclonal antibody. The study included 59 samples of non‐neoplastic mucosa, 45 polyps (11 hyperplastic, 34 adenomas), 196 carcinomas, and lymph node metastases of 87 carcinomas. Epithelial cells of normal mucosa and hyperplastic polyps were negative or showed weak positivity in the paranuclear and apical areas of the cytoplasm. In adenomas and carcinomas, the staining was stronger, with a membranous or cytoplasmic pattern. The expression of 67LR correlated significantly with the progression from normal mucosa (22 per cent) to adenoma (44 per cent), carcinoma (61 per cent), and lymph node metastasis (75 per cent) (P<0·0001). Expression of the laminin receptor showed a tendency to be more frequently positive in advanced stage (III+IV; 67 per cent) when compared with early stage (I+II) carcinomas (54 per cent). The difference, however, was not statistically significant (P=0·058). In addition, 14 out of 28 (50 per cent) primary carcinomas without 67LR expression became positive in lymph node metastases, while most (86 per cent) of the MLuC5‐positive primary carcinomas were also immunoreactive in metastases. In conclusion, these results indicate that 67LR is up‐regulated in the progression of human colorectal carcinomas and may play a role in the local and metastatic progression of these tumours.

INK4a/ARFLocus Alterations in Human Non-Hodgkin's Lymphomas Mainly Occur in Tumors with Wild-Type p53 Gene

INK4a/ARF locus codes for two different proteins, p16(INK4a) and p14(ARF), involved in cell cycle regulation. p14(ARF) is considered an upstream regulator of p53 function. To determine the role of these genes in the pathogenesis of human non-Hodgkins lymphomas we have analyzed exon 1beta, 1alpha, and 2 of the INK4a/ARF locus and p53 gene aberrations in 97 tumors previously characterized for p16(INK4a) alterations. p53 alterations were detected in four of 51 (8%) indolent lymphomas but in 15 of 46 (33%) aggressive tumors. Inactivation of p14(ARF) was always associated with p16(INK4a) alterations. Exon 1beta was concomitantly deleted with exon 1alpha and 2 in eight tumors. One additional lymphoblastic lymphoma showed deletion of exon 1alpha and 2 but retained exon 1beta. No mutations were detected in exon 1alpha and 1beta in any case. Two of the three mutations detected in exon 2 caused a nonsense mutation in the p16(INK4a) reading frame and a missense mutation in the ARF reading frame involving the nucleolar transport domain of the protein. The third mutation was a missense mutation in the p16(INK4a) reading frame, but it was outside the coding region of p14(ARF). Aggressive lymphomas with p14(ARF) inactivation and p53 wild type showed a significantly lower p53 protein expression than tumors with no alteration in any of these genes. In this series of tumors, inactivation of the INK4a/ARF locus mainly occurred in tumors with a wild-type p53 gene because only two lymphomas showed simultaneous aberrations in these genes. Tumors with concomitant alterations of p16(INK4a) and p14(ARF)/p53 genes seem to exhibit a worse clinical behavior than lymphomas with no alterations or isolated inactivation of any of these genes. These findings indicate that p14(ARF) genetic alterations occur in a subset of aggressive NHLs, but they are always associated with p16(INK4a) aberrations. Concomitant disruption of p16(INK4a) and p14(ARF)/p53 regulatory pathways may have a cooperative effect in the progression of these tumors.

Mesonephric adenocarcinoma of the uterine corpus: CD10 expression as evidence of mesonephric differentiation.

Mesonephric (wolffian) neoplasms of the female genital tract are infrequent and found in sites where embryonic remnants of wolffian origin are usually detected, such as the uterine cervix, broad ligament, mesosalpinx, and ovary. Their diagnosis is difficult because of the absence of specific immunohistochemical markers for mesonephric derivatives. We present the first report of adenocarcinoma of mesonephric type arising as a purely myometrial mass without endometrial or cervical involvement in the uterine corpus of a 33-year-old woman. The tumor showed a combination of patterns, with retiform areas, ductal foci, and small tubules with eosinophilic secretion, which merged with solid sheets of cells with a sarcomatoid appearance. Immunohistochemically, neoplastic cells were diffusely positive for cytokeratin 7, epithelial membrane antigen, and CD15 and focally positive for BerEP4 and vimentin. A hitherto unreported feature was the positivity for CD10 in neoplastic cells, which was also present in a large number of control tissues obtained from male mesonephric derivatives and female mesonephric remnants and tumors. Furthermore, CD10 was negative in controls from müllerian epithelia of the female genital tract and in their corresponding tumors. Therefore, the expression of CD10 by mesonephric remnants may be useful in establishing the diagnosis of tumors with mesonephric differentiation.

Adenosquamous carcinoma of the head and neck: criteria for diagnosis in a study of 12 cases

Aims:  Adenosquamous carcinoma (ASC) of the head and neck is an unusual neoplasm in which a general consensus with regard to diagnostic criteria has not yet been reached. In this study we report the clinicopathological results of 12 ASCs, with special attention to their histological and immunohistochemical characteristics in order to define this neoplasm more precisely.

Placental Malaria Is Associated with Cell-Mediated Inflammatory Responses with Selective Absence of Natural Killer Cells

Immunosuppression, particularly of cell-mediated responses, has classically been thought to play a major role in the increased susceptibility to malaria observed in pregnant women. An immunohistochemical characterization of the inflammatory infiltrate in a group of 41 placentas from women living in a Plasmodium falciparum-hyperendemic area in Tanzania revealed a marked increase in the number of monocytes and macrophages and cytotoxic T cells in the intervillous space of placentas with active malaria infection, compared with noninfected placentas, placentas from women with past infection, and a control group of placentas from Spain. This increase was associated with the severity of the infection. High numbers of monocytes and macrophages were associated with low birth weight. We also detected a complete absence of NK cells in the intervillous space in all placentas. This apparently physiological absence of NK cells may contribute to hindering the clearance of the parasite. These results indicate that placental malaria does not appear to be associated with cell-mediated immunosuppression. The role of the absence of NK cells in increased susceptibility to malaria needs to be further elucidated.

Incidence and Prognostic Impact of Secondary Cytogenetic Aberrations in a Series of 145 Patients with Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a mature B‐cell neoplasm with an aggressive behavior, characterized by the t(11;14)(q13;q32). Several secondary genetic abnormalities with a potential role in the oncogenic process have been described. Studies of large MCL series using conventional cytogenetics, and correlating with proliferation and survival, are scarce. We selected 145 MCL cases at diagnosis, displaying an aberrant karyotype, from centers belonging to the Spanish Cooperative Group for Hematological Cytogenetics. Histological subtype, proliferative index and survival data were ascertained. Combined cytogenetic and molecular analyses detected CCND1 translocations in all cases, mostly t(11;14)(q13;q32). Secondary aberrations were present in 58% of patients, the most frequent being deletions of 1p, 13q and 17p, 10p alterations and 3q gains. The most recurrent breakpoints were identified at 1p31‐32, 1p21‐22, 17p13, and 1p36. Aggressive blastoid/pleomorphic variants displayed a higher karyotypic complexity, a higher frequency of 1p and 17p deletions and 10p alterations, a higher proliferation index and poor survival. Gains of 3q and 13q and 17p13 losses were associated with reduced survival times. Interestingly, gains of 3q and 17p losses added prognostic significance to the morphology in a multivariate analysis. Our findings confirm previous observations indicating that proliferation index, morphology and several secondary genetic alterations (3q gains and 13q and 17p losses) have prognostic value in patients with MCL. Additionally, we observed that 3q gains and 17p losses detected by conventional cytogenetics are proliferation‐independent prognostic markers indicating poor outcome.

Epstein-Barr virus negative clonal plasma cell proliferations and lymphomas in peripheral T-cell lymphomas: a phenomenon with distinctive clinicopathologic features.

Clonal B-cell populations have been described in peripheral T-cell lymphomas (PTCL) as secondary Epstein-Barr virus (EBV) driven B-cell expansions that may evolve to an overt B-cell lymphoma. EBV-negative B-cell proliferations associated with T-cell lymphomas are uncommon and not well characterized. We studied 15 patients who developed an EBV-negative B-cell proliferation or malignant lymphoma associated with PTCL. The T-cell tumors were 8 PTCL, not otherwise specified, 4 angioimmunoblastic T-cell lymphomas, and 3 cutaneous PTCL. The B-cell component was intermingled with the PTCL in all patients and it was classified as clonal/monotypic plasma cell proliferation in 8 lesions, clonal/monotypic large B-cell proliferation in 4 patients, and B-cell lymphoma with plasmacytic/plasmablastic differentiation in 3 patients. Two patients had 2 clonally unrelated plasma cell proliferations associated with the same PTCL. All cases showed cytoplasmic Ig light chain restriction. Clonal IgH and T-cell receptor rearrangements were detected in 11/12 and 11/13 cases examined, respectively. EBV, cytomegalovirus, and HHV-8 were not observed in any of the examined cases. Sequential samples in 7 patients showed persistence of the PTCL and the B-cell component in 4, the PTCL without the B-cell lymphoma in 2, and progression of the B-cell neoplasm in 1. Patients followed an aggressive clinical course similar to conventional PTCL. In conclusion, EBV-negative clonal or mononotypic B-cell proliferations in patients with PTCL present with a spectrum of lesions ranging from plasma cell proliferations to overt lymphomas with plasmacytic/plasmablastic features. The distinctive features of these patients suggest that these lesions represent a specific phenomenon in PTCL.

c-myc mRNA expression and genomic alterations in mantle cell lymphomas and other nodal non-Hodgkin’s lymphomas

Cyclin D1 is a weak oncogene that cooperates with c-myc activation in the development of B cell lymphomas in transgenic animals. Cyclin D1 is constantly overexpressed in human mantle cell lymphomas (MCL). However, the status of c-myc gene in these tumors is not known. We have examined the c-myc mRNA expression and genomic alterations, including mutational analysis of exon 1, intron 1, and exon 2 regulatory elements, in a series of 33 MCL, 22 typical and 11 blastoid variants. In addition, c-myc alterations were also examined in 56 nodal non-Hodgkin’s lymphomas (NHL). c-myc mRNA overexpression was found in 38% (11/29) of MCL with a slightly higher frequency in blastoid variants (5/10, 50%) than in typical cases (6/19, 31%). Genetic alterations were only found in one blastoid MCL showing a three-fold c-mycgene amplification. In other nodal NHL, c-myc overexpression was found in 24% (7/29) of indolent tumors but in 70% (19/27) of aggressive variants. c-myc Genetic alterations detected in these cases were gene rearrangement and hypermutations in one Burkitt’s lymphoma, and individual point mutations in intron 1 or exon 2 in 1/19 (5%) indolent and 7/16 (44%) aggressive variants. These results indicate that c-myc is overexpressed in a subset of MCL, but structural gene alterations are less frequent than in other nodal NHL.