Claudin 6 is associated with a short survival and a short recurrent free interval in non-small cell lung carcinoma.

We investigated the expression of claudin 6 in non-small-cell lung carcinomas (NSCLC) by immunohistochemistry. Samples of 164 patients with NSCLC were studied by immunohistochemistry. Claudin 6 was expressed in 42 % of cases. Its expression was significantly more frequent in adeno- than in squamous cell carcinoma (p = 0.002). There was no association between the TNM status and claudin 6 expression. Claudin 6 associated with a poor prognosis of the patients and with a short recurrence-free interval (p = 0.002, p < 0.001). The association with survival had independent prognostic value (p = 0.011). The results show that claudin 6 can be regarded as a marker of poor prognosis in lung cancer. This is different to some other cancers, such as breast and cervical carcinoma suggesting that claudin 6 probably induces other cellular pathways in neoplastic lung cells than in those tumors. In lung cancer, adenocarcinomas were most abundantly positive indicating a higher linkage of claudin 6 to glandular differentiation.

Different chemokine profile between systemic and testicular diffuse large B-cell lymphoma.

Although treatment for diffuse large B-cell lymphoma (DLBCL) has taken some notable steps in the 2000s, there are still subgroups of patients suffering from high mortality and relapse rates. To further improve treatment outcomes, it is essential to discover new mechanisms of chemotherapy resistance and create new treatment approaches to overcome them. In the present study, we analyzed the expression of chemokines and their ligands in systemic and testicular DLBCL. From our biopsy sample set of 21 testicular and 28 systemic lymphomas, we were able to demonstrate chemokine profile differences and identify associations with clinical risk factors. High cytoplasmic CXCL13 expression had correlations with better treatment response, lower disease-related mortality, and limited stage. This study suggests that active CXCR5/CXCL13 signaling could overtake the CXCR4/CXCL12 axis, resulting in a better prognosis.

Testis-Specific Thioredoxins TXNDC2, TXNDC3, and TXNDC6 Are Expressed in Both Testicular and Systemic DLBCL and Correlate with Clinical Disease Presentation.

DLBCL is the most common type of non-Hodgkin lymphoma with a substantial group of patients suffering a poor prognosis. Therefore more specific markers are required for better understanding of disease biology and treatment. This study demonstrates that testis-specific antioxidant enzymes TXNDC2, TXNDC3, and TXNDC6 alongside oxidative stress marker 8-OHdG are expressed in both testicular and systemic DLBCL, and their presence or absence has correlations with clinical risk factors such as the number of extranodal effusion, the appearance of B-symptoms, and treatment response. Biopsy samples were collected from 28 systemic and 21 testicular male DLBCL patients. The samples were histostained with TXNDC2, TXNDC3, TXNDC6, and 8-OHdG, then graded by a hematopathologist blinded to clinical data. Immunoelectron microscopy was used as a second method to confirm the reliability of the acquired immunohistochemistry data. The absence of nuclear TXNDC2 expression in testicular DLBCL cells correlated with worse primary treatment response, cytoplasmic TXNDC3 expression in testicular and systemic DLBCL associated with lower frequency of B-symptoms, and TXNDC6 expression in cytoplasm in systemic DLBCL had a clinical significance with higher LD levels suggesting a role in the biological nature of these lymphomas. Overall, TXNDC3 cytoplasmic expression is correlated with a more positive outcome in both testicular and systemic DLBCL, while TXNDC6 cytoplasmic expression is associated with a negative outcome in systemic DLBCL.

Thioredoxin-1 as a biological predictive marker for selecting diffuse large B-cell lymphoma patients for etoposide-containing treatment.

OBJECTIVE: In diffuse large B-cell lymphoma (DLBCL), there is an unmet medical need to select patients who would benefit from intensified frontline treatments such as adding etoposide to an R-CHOP regimen. METHODS: The present work included a retrospective clinical analysis of two patient cohorts and an in vitro study. Primary biopsy samples from DLBCL patients treated with an etoposide-containing high-dose regimen (n = 37) and etoposide-containing frontline treatment (n = 69, R-CHOEP) were studied using immunohistochemical thioredoxin-1 (Trx1) staining. Two DLBCL cell lines expressing Trx1 were cultured, and their expression was silenced using the small interfering RNA knockdown technique. Chemoresistance was tested with doxorubicin, etoposide, vincristine, prednisolone and carboplatin. RESULTS: Thioredoxin-1 knockdown sensitised DLBCL cells to doxorubicin (P < .0001) but decreased etoposide-induced cell death (P < .00001). In DLBCL patients who received etoposide-containing frontline treatment, low cytoplasmic Trx1 expression was associated with inferior 5-year overall survival (46% vs 76%, P = .026) and disease-specific survival (68% vs 90%, P = .026). CONCLUSIONS: Strong Trx1 expression appears to increase drug resistance to doxorubicin but sensitises cells to etoposide. This implies that Trx1 expression might be the first predictive biological marker to select the patients who might benefit from adding etoposide to R-CHOP immunochemotherapy.

Nuclear factor erythroid 2-related factors 1 and 2 are able to define the worst prognosis group among high-risk diffuse large B cell lymphomas treated with R-CHOEP.

AIMS: Oxidative stress markers and antioxidant enzymes have previously been shown to have prognostic value and associate with adverse outcome in patients with diffuse large B cell lymphoma (DLBCL). Nuclear factor erythroid 2-related factor 1 (Nrf1) and factor 2 (Nrf2) are among the principal inducers of antioxidant enzyme production. Kelch ECH associating protein 1 (Keap1) is a negative regulator of Nrf2, and BTB (BR-C, ttk and bab) domain and CNC homolog 1 (Bach1) represses the function of both factors. Their significance in DLBCL prognosis is unknown. METHODS: Diagnostic biopsy samples of 76 patients with high-risk DLBCL were retrospectively stained with immunohistochemistry for Nrf1, Nrf2, Keap1 and Bach1, and correlated with clinical data and outcome. RESULTS: Nuclear Nrf2 and nuclear Bach1 expression were associated with adverse clinical features (anaemia, advanced stage, high IPI, high risk of neutropaenic infections), whereas cytoplasmic Nrf1 and Nrf2 were associated with favourable clinical presentation (normal haemoglobin level, no B symptoms, limited stage). None of the evaluated factors could predict survival alone. However, when two of the following parameters were combined: high nuclear score of Nrf2, low nuclear score of Nrf1, high cytoplasmic score of Nrf1 and low cytoplasmic score of Keap1 were associated with significantly worse overall survival. CONCLUSIONS: Nrf1 and Nrf2 are relevant in disease presentation and overall survival in high-risk DLBCL. Low nuclear expression of Nrf1, high cytoplasmic expression of Nrf1, high nuclear expression of Nrf2 and low cytoplasmic expression of Keap1 are associated with adverse outcome in this patient group.

KDM4A, KDM4B and KDM4C in non-small cell lung cancer.

KDM4A, KDM4B and KDM4D are lysine demethylases which demethylate H3 at lysine K9 and K36 sites, additionally KDM4D also the H1.4 linker histone at K26 lysine. Lysine methylation changes can repress or induce gene expression at specific sites thus influencing cellular functions. We analysed the immunohistochemical expression of KDM4A, KDM4B and KDM4D in a clinical material of 188 patients with lung carcinomas. There were 132 (70%) squamous cell carcinomas, 53 (28%) adenocarcinomas and 3 (2%) large cell carcinomas in the study. Additionally, the trimethylated state of chromatin was detected with an antibody to trimethylated H3K9 residue. Nuclear KDM4A and KDM4D were associated with the presence of lymph node metastases in tumors. Cytoplasmic KDM4A was associated with poor survival of the patients (P = 0.015) and with a shorter recurrence free interval (P = 0.028). KDM4A and KDM4D appear to have a significant role in the metastatic spread of lung carcinomas. The findings are also in line with their proposed involvement in mechanisms associated with cell proliferation, apoptosis and DNA repair.

Accumulation of genomic alterations in 2p16, 9q33.1 and 19p13 in lung tumours of asbestos-exposed patients.

We have previously demonstrated an association between genomic alterations in 19p13, 2p16, and 9q33.1 and asbestos exposure in patients' lung tumours. This study detected allelic imbalance (AI) in these regions in asbestos-exposed lung cancer (LC) patients' histologically normal pulmonary epithelium. We extended the analyses of tumour tissue to cover a large LC patient cohort and studied DNA copy number alteration (CNA) and AI in 19p13, 2p16, and 9q33.1 for the first time in combination. We found both CNA and AI in ≥2/3 of the regions to be significantly and dose-dependently (P < 0.001) associated with pulmonary asbestos fibre count. Twenty percent of the exposed patients' LC showed CNA in ≥2/3 of the regions, whereas none of the non-exposed patients' LC showed CNA in more than one region. AI was evident in 89% of the exposed and in only 26% of the non-exposed patients' LC. The genomic alterations in 19p13, 2p16, and 9q33.1 in compilation identified asbestos-exposed patients' lung tumours better than each of the regions alone. These alterations form the basis for the development of a combinatorial molecular assay that could be used to identify asbestos-related LC.

Strong expression of HSP47 in metaplastic nasal mucosa may predict a poor outcome after primary endoscopic dacryocystorhinostomy: a prospective study.

PURPOSE: Dacryocystorhinostomy (DCR) is an effective and safe procedure for patients with post-saccal obstruction of the nasolacrimal pathway. The aim of DCR is to relieve symptoms by creating a bypass between the lacrimal sac and the nasal cavity. The most common reason for failure is stenosis caused by a fibrotic process at the rhinostomy site. In this prospective study we assessed the expression of heat shock protein 47 (HSP47), a regulator of fibrosis, in the biopsies of nasal mucosa isolated from patients undergoing primary endoscopic DCR (EN-DCR). METHODS: Thirty consecutive primary EN-DCR procedures in 30 patients were performed using the powered instrumentation technique. The nasal mucosa specimens over the rhinostomy site were collected for histological analysis at the beginning of the operation and the expression of HSP47 was evaluated by immunohistochemistry. The outcome of EN-DCR was estimated in follow-up visits at 1 week, 2 months and 6 months after surgery. RESULTS: At the 6-month follow-up, the overall success rate after primary EN-DCR was 83%. A metaplastic change and strong expression of HSP47 in nasal mucosa were associated with EN-DCR failure (p = 0.009). CONCLUSIONS: HSP47 may be regarded as a novel marker to predict impaired EN-DCR outcome.

Reduced gamma-catenin expression and poor survival in oral squamous cell carcinoma.

OBJECTIVE: To investigate whether reduced expression of alpha-, beta-, or gamma-catenin predicts poor survival in oral squamous cell carcinoma (OSCC). DESIGN: Immunohistochemical analyses of a retrospective cohort. SETTING: University-affiliated hospital. PATIENTS: One hundred twenty-four patients with OSCC. MAIN OUTCOME MEASURE: The prognostic value of gamma-catenin expression on disease-specific survival in different T and N category groups in patients with OSCC. RESULTS: Reduced expression of gamma-catenin correlated with poor tumor differentiation of OSCC (P = .04). Patients with reduced gamma-catenin expression in the primary tumor had significantly more frequent lymph node metastasis than did patients with normal gamma-catenin expression (P = . 03). Reduced expression of gamma-catenin (004) but not of alpha-catenin (P = .25) or beta-catenin (P = .48) correlated with poor clinical outcome. Reduced gamma-catenin expression predicted poor disease-specific survival also in the 92 patients with T1 or T2 tumors (P = . 02). In multivariate analysis, advanced T category (P = . 04), neck lymph node metastases (P = . 01), and reduced gamma-catenin expression (P = . 05) were independently related to poor survival. CONCLUSIONS: Reduced expression of gamma-catenin was associated with poor differentiation of OSCC, with neck lymph node metastases, and, more importantly, with poor disease-specific survival. Loss of gamma-catenin expression seems to contribute to metastatic properties of OSCC. Evaluation of the expression pattern of gamma-catenin may be useful for predicting outcome in patients with OSCC.

Molecular alterations at 9q33.1 and polyploidy in asbestos-related lung cancer.

PURPOSE: Asbestos causes DNA damage and the fibers, together with tobacco smoke, have a synergistic effect on lung cancer risk. We recently identified 18 chromosomal regions that showed differences in DNA copy number between the lung tumors of asbestos-exposed and nonexposed patients. One of the previously identified asbestos-associated chromosomal regions at 9q was further analyzed for allelic imbalance and DNA copy number alterations (CNA) in the lung tumors of asbestos-exposed and nonexposed patients. In addition, the ploidy level of the tumors was studied. EXPERIMENTAL DESIGN: Allelic imbalance was analyzed at 9q31.3-34.3 with 15 microsatellite markers in 52 lung tumor samples from asbestos-exposed and nonexposed patients. CNA at 9q32-34.3 were characterized by fluorescent in situ hybridization (FISH) with six bacterial artificial chromosome probes in 95 lung tumors. The ploidy level was analyzed in 100 lung tumors with FISH using three to five centromere probes. RESULTS: Allelic imbalance at 9q31.3-q34.3 was found in all asbestos-exposed patient tumors (100%, 17 of 17) compared with 64% (14 of 22) in the nonexposed cases (P = 0.005). The most significant difference was detected at 9q33.1 (P = 0.002). FISH results showed that also CNA were more frequent at 9q33.1 in the three major histologic types of non-small-cell lung tumors of exposed patients, and the association showed a dose-dependent trend (P = 0.03). Furthermore, we detected more frequent polyploidy among the exposed (48%, 28 of 58) than among the nonexposed (29%, 12 of 42) patient tumors (P < 0.05). CONCLUSIONS: These results provide a basis for the development of a method to identify asbestos-related lung cancer on a molecular level.

Oncolytic Semliki forest virus vector as a novel candidate against unresectable osteosarcoma.

Oncolytic viruses are a promising tool for treatment of cancer. We studied an oncolytic Semliki Forest virus (SFV) vector, VA7, carrying the enhanced green fluorescent protein gene (EGFP), as a novel virotherapy candidate against unresectable osteosarcoma. The efficiency and characteristics of the VA7-EGFP treatment were compared with a widely studied oncolytic adenovirus, Ad5Delta24, both in vitro and in vivo. VA7-EGFP resulted in more rapid oncolysis and was more efficient at low multiplicities of infection (MOI) when compared with Ad5Delta24 in vitro. Yet, in MG-63 cells, a subpopulation resistant to the VA7-EGFP vector emerged. In subcutaneous human osteosarcoma xenografts in nude mice treatment with either vector reduced tumor size, whereas tumors in control mice expanded quickly. The VA7-EGFP-treated tumors were either completely abolished or regressed to pinpoint size. The efficacy of VA7-EGFP vector was studied also in an orthotopic osteosarcoma nude mouse model characterized by highly aggressive tumor growth. Treatment with oncolytic SFV extended survival of the animals significantly (P < 0.01), yet none of the animals were finally cured. Sera from SFV-treated mice contained neutralizing antibodies, and as nude mice are not able to establish IgG response, the result points out the role of IgM class antibodies in clearance of virus from peripheral tumors. Furthermore, biodistribution analysis at the survival end point verified the presence of virus in some of the brain samples, which is in line with previous studies demonstrating that IgG is required for clearance of SFV from central nervous system.

Replication competent Semliki Forest virus prolongs survival in experimental lung cancer.

We evaluated the therapeutic potential of the replication competent vector VA7-EGFP, which is based on the avirulent Semliki Forest virus (SFV) strain A7 (74) carrying the EGFP marker gene in an orthotopic lung cancer tumor model in nude mice. We have previously shown that this oncolytic vector destroys tumor cells efficiently in vitro and in vivo (in subcutaneous tumor model). Tumor growth in animals with orthotopically implanted adenocarcinoma cells (A549) were monitored during the study with small animal CT. We show that locally administered virotherapy with VA7-EGFP increased survival rate in experimental lung cancer significantly (p < 0.001) comparable to results obtained with the second generation conditionally replicating adenoviral vector Ad5-Delta24TK-GFP, used for comparison. The limited efficacy in systemically administered oncolytic viruses is the essential problem in oncolytic virotherapy and also in this study we were not able to elicit significant response with systemic administration route. Despite the fact that tumor microenvironment in orthotopic lung cancer is more optimal, viruses failed to home to the tumors and were unable to initiate efficient intratumoral replication. Clearly, the efficacy of virotherapy is influenced by many factors such as the route of virus administration, immunological and physiological barriers and cancer cell-specific features (IFN-responsiveness).

Hyaluronan in human tumors: pathobiological and prognostic messages from cell-associated and stromal hyaluronan.

Cancers are supported by a distinct type of connective tissue stroma, crucial for tumor survival and advancement. Hyaluronan is a major matrix molecule in the stroma of many common tumors, and involved in their growth and spreading. Here we focus in recent data on stromal hyaluronan in human tumors, and that on the surface of the malignant cells. Hyaluronan accumulation is most conspicuous in malignancies that develop in cells and tissues normally devoid of hyaluronan, such as single layered epithelia and their hyaluronan-poor connective tissue stroma. The magnitude of the hyaluronan accumulation in the malignant epithelium itself (e.g. colon and gastric cancers) or tumor stroma (breast, ovarian, prostate cancers) strongly correlates with an unfavorable prognosis of the patient, i.e. advancement of the malignancy. A completely different pattern arises from stratified epithelia that normally produce hyaluronan and are surrounded by a hyaluronan-rich stroma. The cell surface of the latter group of tumors (e.g. squamous cell carcinomas of skin, mouth, larynx and esophagus, and skin melanoma) show abundant hyaluronan which tends to get reduced and patchy in the most advanced stages of the tumors, suggesting enhanced turnover. While the assays of human tumors represent snapshots of currently unknown processes and kinetics of hyaluronan metabolism, it is obvious that hyaluronan accumulation at some stage is an inherent feature in most of the common epithelial malignant tumors. The possible contributions of inflammatory cells, stem cells, mutated stromal cells, or otherwise deranged growth factor exchange between stromal and cancer cells are discussed as possible explanations to hyaluronan abundance in the tumors. The importance of hyaluronan in human tumor progression will be further clarified when drugs become available to modify hyaluronan metabolism.

Increased expression of matrix metalloproteinase-2 (MMP-2) predicts tumour recurrence and unfavourable outcome in non-small cell lung cancer.

The purpose of this study was to analyse the expression of matrix metalloproteinase-2 (MMP-2) and its extracellular matrix metalloproteinase inducer (EMMPRIN) in non-small cell lung cancer (NSCLC), and to evaluate their significance to predict tumour behaviour. The study consists of 212 patients treated by the resection of the tumour. Tumour samples were stained immunohistochemically, and the expression of MMP-2 and EMMPRIN was evaluated both in tumour cells and in peritumoural stromal tissue. The results were compared with clinicopathological factors and survival of the patients. High expression of MMP-2 in tumour cells was found in 83 out of 191 cases (44%). Adenocarcinomas showed more often high expression of MMP-2 as compared with squamous cell or large cell carcinomas (p=0.001). High cancer cell associated MMP-2 expression was associated with increased tumour recurrence (p=0.001). Tumour stroma showed positive staining in 162 (98%) cases and was considered highly stained in 120 (72%) cases. The high stromal MMP-2 expression was noticed more often among large cell carcinomas as compared with other histological types (p=0.007). High cancer cell associated EMMPRIN expression was found in 115 (61%) cases and was associated only with high MMP-2 expression in tumour cells (p=0.006). In overall survival (OS) and disease free survival (DFS) analyses, type of tumour (p=0.001 and p=0.0004), advanced stage (p=0.001 and p=0.013) and high MMP-2 expression in tumour cells (p=0.018 and p=0.001) were associated with poor survival. Also, high stromal MMP-2 expression was related to poor outcome in both OS and DFS analyses (p=0.010 and 0.045, respectively). In multivariate analysis, stromal MMP-2 expression retained its prognostic value to predict OS and DFS (p=0.028 and p=0.039, respectively), together with tumour type and stage (p=0.017, p=0.001 and p=0.021, p=0.008, respectively). The present study shows the significant prognostic value of MMP-2 in NSCLC suggesting that the use of MMP-2 is valuable in determining the patients with more aggressive disease.

High stromal versican expression predicts unfavourable outcome in oral squamous cell carcinoma.

BACKGROUND: Versican, an extracellular matrix proteoglycan, has been noted to be expressed in several malignant tumours and has been suggested to play an important role in cancer development and tumour growth. AIMS: To investigate whether the versican expression level in the peritumoural stromal tissue of primary oral squamous cell carcinoma (OSCC) predicts relapse-free or disease-specific survival. Also, to study the associations between versican expression and several other clinicopathological variables, as well as tumour cell proliferation. METHODS: Immunohistochemistry was used to study the expression of versican and tumour cell proliferative activity in 139 OSCCs. All pertinent clinical data were collected retrospectively from the hospital records. RESULTS: In this cohort, versican expression did not correlate with the clinicopathological factors or tumour cell proliferation. In univariate analyses, higher risk for disease recurrence was associated with higher stromal versican expression score (p = 0.02), positive neck node status (p = 0.02), lower Karnofsky performance status (p = 0.03) and higher tumour cell proliferation index (p = 0.04). Increased disease-specific risk of death was associated with high stromal versican expression score (p = 0.005) higher T class (p = 0.002), positive neck node status (p<0.001), higher stage (p<0.001), poorer histological differentiation (p = 0.005), worse general condition of the patient (p = 0.049) and increased tumour cell proliferative index (p = 0.02). In multivariate disease-specific survival analysis, high stromal versican expression score (p = 0.048), poorer histological differentiation (p = 0.047) and higher stage (p = 0.002) independently predicted poorer disease outcome. CONCLUSIONS: In this cohort, increased stromal versican expression correlated with both increased risk for disease recurrence and shortened survival. High stromal versican expression may thus be considered an independent and adverse prognostic marker in OSCC.

Expression of matrix metalloproteinases 7 and 9 in non-small cell lung cancer. Relation to clinicopathological factors, beta-catenin and prognosis.

Matrix metalloproteinases (MMPs) have been shown to have a significant role in determining cancer cell behaviour. The present study was undertaken to analyze the expression and prognostic value of MMP-7 and MMP-9 in non-small cell lung cancer (NSCLC). The relationship of MMP-7 with beta-catenin was also evaluated. The study consists of 212 patients with resected NSCLC. Tumour samples were stained immunohistochemically, and the expression of MMP-7 and MMP-9 was evaluated in both tumour cells and peritumoural stromal tissue. The results were compared to clinicopathological factors of the patients. A high staining of MMP-7 and MMP-9 in tumour cells was noted in 62 (30%) and 113 (57%) cases, respectively. Expression of MMP-7 was noted more often in adenocarcinomas than in other histological types (p=0.022). High cancer cell associated MMP-7 was related to lower T-factor (p=0.037), better tumour differentiation (p=0.005) and normal beta-catenin expression in tumour cells (p=0.001). A high MMP-9 expression in tumour cells was related to poor tumour differentiation (p=0.016). The stromal signal for MMP-9 was observed in 58 (32%) cases and was linked with higher tumour grade (p=0.031). In survival analyses the significant predictors of survival were histological type of tumour and tumour stage (p=0.0009 and 0.0012, respectively). MMP-7 or MMP-9 signals were not related to patient's outcome. The results show that high MMP-9 expression indicates aggressive, and high MMP-7 less aggressive tumour behaviour in NSCLC. However, MMP-7 and MMP-9 expressions had no prognostic value in NSCLC.

Versican in nonsmall cell lung cancer: relation to hyaluronan, clinicopathologic factors, and prognosis.

The aim of the study was to investigate the expression and prognostic role of versican in 212 patients with resected nonsmall cell lung cancer. Tumor samples were stained immunohistochemically, and the versican staining was evaluated both in tumor stroma and cancer cells. The staining results were compared to the clinical data of the patients, the tumor cell proliferation, and the expression of hyaluronan. In the whole material, low and high area percentages of stromal versican staining were observed in 135 and 77 carcinomas, respectively. Tumor cell-associated staining signal for versican was observed in 33 cases. In the whole material, the significant relationship between high stromal staining of versican and that of hyaluronan was noticed (P = .001). The expression of stromal versican was related to tumor type (P = .008) and high stromal staining was inversely correlated with poor tumor differentiation (P = .045), but not with tumor cell proliferation. Among adenocarcinomas, the high stromal staining of versican was associated with tumor recurrence (P = .024), higher tumor stage (P = .022), and lymph node metastases (P = .042). Versican expression was not related to patient outcome in the whole material, but among adenocarcinomas, the high stromal staining was related to poor disease-free survival (P = .0056). However, in Cox multivariate analysis with tumor stage, versican expression did not retain its prognostic significance. The results indicate that increased stromal versican is related to higher tumor recurrence rate and more advanced disease. Despite the important role of versican in nonsmall cell lung cancer, traditional clinicopathologic factors remained most significant in the current study.

Hyaluronan expression in differentiated thyroid carcinoma.

The extracellular polysaccharide hyaluronan (HA) controls cell migration, differentiation, and proliferation, and is supposed to contribute to the spreading of several human cancers. Little is known about the role of HA in the development and progression of differentiated thyroid carcinoma (DTC). The expression and prognostic value of HA were therefore evaluated in 204 consecutive patients with DTC. A biotinylated affinity probe specific for HA was applied to paraffin-embedded tumour samples to assay the expression of HA in carcinoma cells and in intra/peritumoural stroma. In a majority of the samples, a high percentage (>or=90%) of normal thyroid follicle epithelial cells were HA-positive. This high percentage was also found in 80 (47%) papillary carcinomas, but only in seven (21%) follicular carcinomas (p=0.004). Age (>60 years) of the patients was significantly associated with a low percentage of HA-positive cancer cells (p=0.013). Cancer cell-associated HA correlated significantly with the percentage of cells expressing total CD44 and its isoforms containing exons v3 and v6 (r=0.223-0.289, p<0.001 for all). The tumour stroma was always positive for HA. Stromal staining intensity did not differ markedly between papillary and follicular carcinomas. A strong stromal HA staining intensity was related to distant metastases (p=0.044), high pTNM stage (p=0.024), old age (>60 years) (p=0.043), and cancer-related mortality (p=0.001). In a log-rank univariate survival analysis, strong stromal HA staining intensity was related to DTC mortality (p=0.0007). Cancer cell-associated HA expression did not significantly correlate with patient survival. In Cox's multivariate survival analysis, age (>60 years, p=0.0164), gender (p=0.0251), and pTNM stage (p=0.0121) were significant independent prognostic factors for DTC-related death. These results suggest that strong stromal HA staining intensity is related to progression and unfavourable outcome in DTC patients, while the clinical factors remain more powerful in predicting DTC-related death.