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Follicular lymphoma (FL) is one of the most common malignant lymphomas. The t(14;18)(q32;q21) translocation is found in about 80% of cases and plays an important role in lymphomagenesis. However, the molecular mechanisms involved in the development and transformation of this lymphoma are not fully understood. Gain-of-function mutations of NOTCH1 or NOTCH2 have recently been reported in several B cell lymphoid neoplasms but the role of these mutations in FL is not known. In this study we investigated the mutational status of these genes in 112 FLs. NOTCH1 and NOTCH2 mutations were identified in five and two cases, respectively (total 7/112, 6.3%). All mutations predicted for truncated protein in the PEST domain and were identical to those identified in other B cell lymphoid neoplasms. NOTCH-mutated FL cases were characterized by lower frequency of t(14;18) (14% versus 69%, p = 0.01), higher incidence of splenic involvement (71% versus 25%, p = 0.02) and female predominance (100% versus 55%, p = 0.04). A diffuse large B cell lymphoma (DLBCL) component was more frequently identified in NOTCH-mutated FL than in wild-type cases (57% versus 18%, p = 0.03). These results indicate that NOTCH mutations are uncommon in FL but may occur in a subset of cases with distinctive, characteristic, clinicopathological features., (Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

ZAP-70 is a tyrosine kinase that participates in early B-cell differentiation and is a prognostic factor in chronic lymphocytic leukaemia (CLL), where it is associated with an unmutated configuration of the IgV(H) genes. In this study ZAP-70 expression was studied by immunohistochemistry in a spectrum of B-cell lymphoid neoplasms; this staining method was compared with flow cytometry, and the relationship of ZAP-70 expression to mutational status and prognosis was assessed. 242 tissue samples from 225 patients with B-cell lymphoid neoplasms arising at different maturational stages were included. Flow cytometry was performed in all CLL cases (n = 52). IgV(H) mutational status was determined in 25 CLL and 12 mantle cell lymphoma (MCL) patients. ZAP-70 was positive in 34/52 (65%) CLL, 9/31 (31%) Burkitt's lymphoma, 2/7 (29%) lymphoblastic lymphomas, 3/36 (8%) MCL, 1/23 (4%) marginal zone lymphoma, and 1/45 (2%) diffuse large B-cell lymphomas, but in none of the 19 follicular lymphomas or the 14 Hodgkin lymphomas. An identical ZAP-70 pattern was obtained in six patients with simultaneous biopsies from different sites and in 12 patients with sequential biopsies. Immunohistochemistry and flow cytometry gave identical results in 48 the 52 CLLs. All but one ZAP-70-positive CLL had IgV(H) gene in an unmutated configuration, whereas all but one ZAP-70-negative CLL had somatically hypermutated IgV(H). The 12 MCLs analysed were ZAP-70 negative regardless of IgV(H) mutational status (4 mutated, 8 unmutated). ZAP-70 positive CLL was associated with a shorter overall survival (median time 103 months vs. 293 months, p = 0.01) and a shorter time to disease progression (median time 26 months vs. 60 months, p = 0.01). In conclusion, ZAP-70 is expressed in several types of B-cell neoplasm and is easily detected by immunohistochemistry, providing a useful prognostic marker in patients with CLL from whom no other material is available or when other techniques for its assessment cannot be performed.

Primary effusion lymphoma (PEL) is a novel lymphoproliferative disorder associated with human herpesvirus 8 (HHV-8) infection. Most PELs develop in HIV-seropositive individuals and are nearly always positive for Epstein-Barr virus (EBV), a finding which obscures the role of HHV-8 in lymphomagenesis. However, rare EBV-negative PEL cases occurring in HIV-seronegative patients have been reported, suggesting that HHV-8 may be pathogenetic by itself. To investigate whether HHV-8 may contribute to PEL development in the absence of EBV, the expression of seven potentially oncogenic HHV-8 open reading frames (ORFs) (ORF72/viral cyclin D, ORF16/viral bcl-2, ORF74/viral G-protein coupled receptor, ORFK2/viral IL-6, ORFK13/viral FLICE inhibitory protein, ORFK9/viral interferon regulatory factor, and ORFK1, equivalent to the gene encoding herpesvirus saimiri transforming protein) was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in an EBV-negative PEL presenting in an HIV-negative patient. RNA transcripts were demonstrated for the seven HHV-8 genes, and this was confirmed by hybridization to specific oligonucleotide probes. The expression of potentially oncogenic HHV-8 genes in this HIV-, EBV-negative PEL case suggests that HHV-8 may induce malignant transformation of B-lymphocytes through different molecular pathways in the absence of EBV infection., (Copyright 1999 John Wiley & Sons, Ltd.)

p27(Kip1) is a cyclin-dependent kinase inhibitor whose down-regulation has been observed in several tumour models, including breast, colorectal, and gastric carcinomas. The purpose of this study was to assess p27(Kip1) protein expression in normal and benign prostatic epithelia as well as the possible existence of abnormalities in prostate carcinoma progression. p27(Kip1) expression was immunohistochemically analysed in 51 normal tissue samples, 11 nodular hyperplasias (NH), 22 high-grade prostatic intraepithelial neoplasias (PIN), 56 localized prostate adenocarcinomas, and 19 metastases. Immunoblotting was performed in ten cases. Normal prostate epithelium and NH showed diffuse and intense p27(Kip1) nuclear expression in most cases. A significant p27(Kip1) down-regulation was observed in many carcinomas when compared with benign epithelium. Forty-seven cases (84 per cent) were low p27(Kip1) expressors (<50 per cent positive cells) and nine cases (16 per cent) were high p27(Kip1) expressors. p27(Kip1) down-regulation was also consistently seen in PIN. Fourteen out of 19 metastases (74 per cent) were low p27(Kip1) expressors. Six metastatic samples had their corresponding primary tumour analysed and three cases showed decreased expression in the metastasis. It is concluded that p27(Kip1) is constitutively expressed in normal and benign prostatic tissue. This expression is clearly down-regulated in neoplastic progression from the preinvasive lesions through invasive carcinoma and metastases and this therefore occurs in early stages of neoplastic transformation., (Copyright 1999 John Wiley & Sons, Ltd.)

Collagenase-3 (MMP-13) is a matrix metalloproteinase recently identified on the basis of differential expression in normal breast tissues and in breast carcinoma. To date, collagenase-3 expression has been reported only in breast carcinomas and in articular cartilage of arthritic patients; the presence and possible implication of this enzyme in the progression of other malignant tumours are unknown. In this study collagenase-3 mRNA expression has been analysed by northern blot in a series of 35 matched squamous cell carcinomas of the larynx and the corresponding adjacent non-neoplastic tissues. In addition, mRNA expression of membrane type 1-matrix metalloproteinase (MT1-MMP) and gelatinase A, two matrix metalloproteinases which have the ability to activate collagenase-3 in vitro, was also examined in the same cases. No collagenase-3 expression was detected in any of the 35 normal mucosae, but collagenase-3 mRNA was observed in 20 of the 35 carcinomas (57 per cent). Western blot analysis revealed the presence of collagenase-3 protein in those carcinomas with high levels of mRNA expression, whereas no protein was detected in the carcinomas with negative mRNA expression, or in any of the normal tissues. The protein was localized predominantly in tumour epithelial cells. Collagenase-3 expression correlated significantly with better histological differentiation of the tumours (p = 0.026), as well as with advanced local invasion (p = 0.026). Collagenase-3 upregulation was also significantly associated with MT1-MMP and gelatinase A overexpression. These findings suggest that collagenase-3 expression may contribute to the progression of a significant subset of squamous cell carcinomas of the larynx and that its coordinate overexpression with MT1-MMP and gelatinase A may have a cooperative effect in the progression of the tumours.

p21WAF1/Cip1 is an inhibitor of cdk/cyclin complexes, and thus regulates the cell cycle. p21 is also related to cell differentiation and is regulated by wild-type p53, although p53-independent regulatory pathways have been proposed. In order to analyse p21 expression as well as its relationship with p53 in human breast cancer, an immunohistochemical analysis was undertaken of 77 breast carcinomas, 16 of them with an in situ component; 30 adjacent normal tissue samples; and five non-neoplastic specimens. Forty-four infiltrating carcinomas (57 per cent) were p21-positive. Expression of p21 was also observed in pre-invasive lesions, whereas normal ducts were negative or focally and weakly positive. p21 expression was associated with high histological grade (II + III) (P = 0.017) and poor tubule formation (P = 0.002), and was significantly less frequent in lobular carcinomas (P = 0.0001). p21 positivity also correlated with increased proliferation, but this seemed to be dependent on the histological grade. Twenty carcinomas (26 per cent) showed p53 overexpression, but this was not associated with p21 negativity, suggesting the existence of p53-independent mechanisms for p21 regulation in vivo. Cyclin D1CCND1 expression was analysed in the same series and an association between p21 and cyclin D1 expression was found, since 23 of 26 cyclin D1-positive carcinomas were p21-positive (P < 0.001 ...). In conclusion, p21 is frequently overexpressed in breast carcinomas and this occurs in the early stages of neoplastic progression. This overexpression seems to be independent of p53 status and might be involved in cyclin D1 modulation.

p21WAF1/Cip1 is a recently identified gene involved in cell cycle regulation through cyclin-CDK-complex inhibition. The expression of this gene in several cell lines seems to be induced by wild-type, but not mutant, p53. p21WAF1/Cip1 expression has been studied at both mRNA and protein levels in a series of 49 normal mucosae and squamous cell carcinomas of the larynx. A significant association was found between mRNA and protein expression in tumours (P < 0.0001). p21WAF1/Cip1 expression was strongly associated with squamous cell differentiation of carcinomas, because six of seven (86 per cent) undifferentiated carcinomas (grade 4) showed very low levels of p21WAF1/Cip1 expression, whereas 41 out of 42 (98 per cent) carcinomas with squamous cell differentiation (grades 1-3) had normal or high levels of p21WAF1/Cip1 expression (P < 0.0001). In addition, p21WAF1/Cip1 expression was topologically related to the squamous differentiation of tumour cells with a distribution similar to that seen in normal squamous epithelium. No correlation was found between p21WAF1/Cip1 expression and the global S-phase of the carcinomas. p53 mutations (exons 5-9) were found in ten carcinomas with p21WAF1/Cip1 expression, but no p53 mutations were detected in three p21WAF1/Cip1-negative tumours. In conclusion, p21WAF1/Cip1 expression is frequently upregulated in squamous cell carcinomas of the larynx and is associated with tumour cell differentiation. p21WAF1/Cip1 expression in these tumours is independent of p53 gene mutations.

Cyclin D1 (CCND1) and retinoblastoma (Rb) genes are cell cycle regulators which are altered in some breast carcinomas. However, the possible cooperation between CCND1 and Rb, as well as the influence and coincidence of their abnormalities in the proliferative capacity of mammary carcinoma cells in vivo, is still unknown. In order to assess both the significance of the CCND1 gene and Rb alterations in breast carcinomas and their relationship with the proliferative capacity of the tumours and other clinico-pathological factors, CCND1 mRNA expression was studied in 46 cases of primary breast carcinomas and matched normal tissue, 45 of which were also studied immunohistochemically, Rb expression was analysed in the same cases by immunohistochemistry, whereas the proliferative activity of the carcinoma was evaluated by flow cytometry. CCND1 mRNA was overexpressed in 19 tumours (41 per cent). Sixteen cases showed diffuse immunohistochemical expression, ten carcinomas had few positive cells, and 19 were absolutely negative. CCND1 mRNA and protein overexpression was associated with oestrogen receptor (ER) expression by the tumour. Interestingly, lack of ER expression was associated with a decreased CCND1 mRNA signal in non-overexpressed tumours. No association was observed between CCND1 mRNA or protein overexpression and tumour proliferation or other clinico-pathological parameters. Loss of Rb expression was observed in 26 per cent of the tumours. This abnormality was significantly associated with increased mean S-phase (P = 0.017) and decreased CCND1 mRNA expression in non-overexpressed tumours, supporting in vivo the postulated regulatory loop between Rb and CCND1 in vitro. We conclude that CCND1 up-regulation is not associated with increased proliferative activity in breast carcinomas, whereas its expression might be regulated in vivo by hormones and Rb. Loss of Rb expression is significantly associated with an increased proliferation of tumour cells, suggesting an important role in the progression of a subset of breast carcinomas, regardless of CCND1 abnormalities.

Galectin-3 is a 31 kD beta-galactoside-binding lectin which is expressed by several types of non-neoplastic and neoplastic cells and which may be involved in cell-extracellular matrix interactions. An immunohistochemical study has been made of the expression of galectin-3, as well as its ligand, laminin, in a spectrum of benign and malignant thyroid neoplasms and in some non-neoplastic conditions. Immunohistochemistry with anti-human recombinant galectin-3 antibody showed consistent, intense positivity in the neoplastic cells of 18 cases of papillary carcinoma and less intense staining in the five anaplastic carcinomas studied. In addition, two out of three poorly differentiated carcinomas, three out of six medullary carcinomas, and four out of eight follicular carcinomas had less intense or focal positivity. One case of Hürthle cell carcinoma showed scattered strongly positive cells. Eight follicular adenomas, three hyperplastic nodules, five nodular goitres, and normal thyroid tissue were negative. Galectin-3 mRNA expression was also evaluated in three of the papillary carcinomas, two follicular adenomas, and one hyperplastic nodule with matched normal tissue. Northern blot analysis demonstrated mRNA overexpression in the three cases of papillary carcinomas, whereas normal and benign tissues were negative. Laminin distribution in neoplastic and non-neoplastic tissue varied with architectural patterns but did not correlate with galectin-3 immunohistochemical expression. We conclude that expression of galectin-3 is limited to inflammatory foci in normal and benign thyroid tissue and is a phenotypic feature of malignant thyroid neoplasms, especially papillary carcinomas.

p53 is a tumour suppressor gene which is often found to be inactivated in most types of human cancer. p53 is a transcription factor, the inactivation of which may lead to significant variations in the levels of p53 downstream proteins, such as p21WAF1/CIP1 and MDM2. In view of the significance of p21WAF1/CIP1 and MDM2 as wild-type (wt) p53 targets, this study was undertaken to monitor the varying expression of these proteins in non-Hodgkin's lymphomas (NHLs) in relation to p53 gene status. A total of 57 cases of different histological types of NHL were included in this study. Proteins p53, p21WAF1/CIP1, and MDM2 were analysed by immunohistochemical techniques, taking the levels expressed in reactive lymphoid tissues as reference points. p53 gene point mutations (exons 5-8) were looked for using the PCR-SSCP technique and direct sequencing. Fifteen of the 57 cases studied showed 16 mutations at the p53 gene: 12 missense, one nonsense, two silent mutations, and one frameshift deletion. Most missense mutations were associated with high levels of p53 protein, while the nonsense mutations and frameshift deletion did not induce detectable levels of p53. All cases with mutation at the p53 gene (15) showed null or low levels of p21WAF1/CIP1 and MDM2 proteins, suggesting that null or missense mutations at this gene give rise to a protein that is unable to transactivate the p21WAF1/CIP1 and MDM2 genes. The association between missense p53 mutation and dissociate immunophenotype (p53+, MDM2-, p21-) was statistically significant (Fisher's exact test, P = 0.0024). This anomalous p53+, MDM2-, p21- phenotype was also found in a small group of five cases with wt p53; this could indicate that in these cases p53 transactivation capacity has been abrogated by a mechanism other than p53 mutation. Most cases with the wt p53 gene show simultaneous immunohistochemical expression of all three proteins and often display higher levels than those found in reactive lymphoid tissue. There is a tendency for EBV-positive cases to harbour high levels of p53+ and p21+, suggesting that EBV could be involved in the nuclear accumulation of p53 and p21WAF1/CIP1 in NHL.

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 (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.

p53 expression has been examined in 89 squamous cell carcinomas of the larynx (34 glottic, 28 supraglottic, 18 transglottic, 8 pyriform sinus, and 1 subglottic) obtained from 88 patients surgically treated in our centre. In addition, 59 laryngeal samples including normal respiratory epithelium and non-invasive squamous cell lesions were also tested. Frozen sections were immunostained with PAb 1801 and the results were correlated with pathological features, DNA ploidy and S-phase of the tumours, disease-free interval, and survival of the patients. p53 immunoreactivity was observed in 57 (64 per cent) carcinomas. None of the eight samples of normal respiratory epithelium was positive. p53-positive cells were seen in 8 of 23 (35 per cent) squamous cell metaplasias, 6 of 19 (32 per cent) low-grade dysplasias and 5 of 10 (50 per cent) high-grade dysplasias. No correlation was found between p53 expression in carcinomas and their clinical and pathological characteristics, DNA ploidy, or proliferative activity. Neither disease-free nor overall survival showed differences between p53-positive and p53-negative cases. These findings indicate that p53 may play a role in an early stage of malignant transformation of a subset of squamous cell carcinomas of the larynx, but seems not to be associated with further progression of the tumours.