New target genes in endometrial tumors show a role for the estrogen-receptor pathway in microsatellite-unstable cancers.

Microsatellite instability (MSI) in tumors results in an accumulation of mutations in (target) genes. Previous studies suggest that the profile of target genes differs according to tumor type. This paper describes the first genome-wide search for target genes for mismatch repair-deficient endometrial cancers. Genes expressed in normal endometrium containing coding repeats were analyzed for mutations in tumors. We identified 44 possible genes of which seven are highly mutated (>15%). Some candidates were also found mutated in colorectal and gastric tumors. The most frequently mutated gene, NRIP1 encoding nuclear receptor-interacting protein 1, was silenced in an endometrial tumor cell line and expression microarray experiments were performed. Silencing of NRIP1 was associated with differences in the expression of several genes in the estrogen-receptor network. Furthermore, an enrichment of genes related to cell cycle (regulation) and replication was observed. We present a new profile of target genes, some of them tissue specific, whereas others seem to play a more general role in MSI tumors. The high-mutation frequency combined with the expression data suggest, for the first time, an involvement of NRIP1 in endometrial cancer development.

Characterization of N-cadherin unbinding properties in non-malignant (HCV29) and malignant (T24) bladder cells.

The expression of N-cadherin, characteristic of various cancers, very often leads to changes in the cells' adhesive properties. Thus, we sought to find out if N-cadherin expressed in various, but cancer-related cells, differs in its functional properties that could contribute to variations in cells' phenotypes. In our work, measurements of an unbinding force of a single N-cadherin molecule, probed with the same antibody both on a surface of living non-malignant (HCV29) and malignant cells (T24) of bladder cancer, were carried out with the use of an atomic force microscopy. The results show the enhanced N-cadherin level in T24 malignant cells (8.7% vs. 3.6% obtained for non-malignant one), confirmed by the Western blot and the immunohistochemical staining. The effect was accompanied by changes in unbinding properties of an individual N-cadherin molecule. Lower unbinding force values (26.1 ± 7.1 pN) in non-malignant cells reveal less stable N-cadherin complexes, as compared to malignant cells (61.7 ± 14.6 pN). This suggests the cancer-related changes in a structure of the binding site of the antibody, located at the extracellular domain of N-cadherin.

[Cysts of the orbital bone and orbital sinus: clinical and morphological characteristics of the three cases]. / Torbiel odosobniona kosci oczodolu i zatoki czolowej: charakterystyka kliniczno-morfologiczna trzech przypadków.

BACKGROUND: Solitary bone cyst is rarely situated in facial bones. AIM: We discuss clinical view, results of radiological examinations and differential histopathological diagnostics of cases. RESULTS: We present 3 cases of patients: 51 year old man with cyst in frontal sinus; 29 year old man and 46 year old woman--both with changes in bones of the orbit. In all the cases results of histopathological examinations were similar. Cystic-shape pieces of vascularizated connective tissue were observed. Multiple cracks filled with cholesterol, macrophages with hemosiderin and occasionally multinuclear cells were noticed. CONCLUSIONS: Solitary bone cyst may be located in the periorbital bone, especially frontal. Excellent laryngological, optic and cosmetic results are results of the surgery. Suspicious of the solitary bone cyst is possible due to MR or CT imaging, but final diagnosis must be confirm by histological examination.

Detection of isolated tumour cells in the blood and bone marrow of patients with gastric cancer by combined sorting, isolation and determination of MAGE-1, -2 mRNA expression.

The detection of isolated (circulating or disseminated) tumour cells (ITC) in patients with cancer requires very sensitive methods, as such cells are very rare. In the present study, the method that combines the negative isolation of CD45- leukocytes from the blood and bone marrow of patients with gastric cancer by flow cytometry, followed by the positive isolation of single cytokeratin-positive (CK+) cells by a Laser Capture Microdissection System for the determination of MAGE-1, -2 mRNA expression was used to detect ITC. This study shows that this method is highly sensitive as it allows to determine beta-actin-mRNA expression in a single CK+ cell. Using > or =5 CK+ cells as a cut-off level, the MAGE-1 mRNA expression was detected in 100% of CK+ cells in the peripheral blood and in 75% of bone marrow samples of patients with gastric cancer. The MAGE-2 mRNA expression was observed in 40 and 58% of samples, respectively. Furthermore, an analysis of primary tumours and locoreginal lymph nodes with respect to the mRNA expression of the two genes showed that MAGE-1 mRNA expression was detected in 88% of the primary tumours and in 67% of the lymph node samples, whereas the MAGE-2 mRNA expression was observed in 72 and 67% of the cases, respectively. Thus, the method described here allows the precise and sensitive determination of tumour-associated gene expression in single ITC present in the blood and bone marrow of patients with gastric cancer.

KRAS mutation profile in colorectal carcinoma and novel mutation--internal tandem duplication in KRAS.

Oncogenic KRAS mutations are associated with resistance to anti-EGFR therapy in colorectal carcinoma. Since anti-EGFR monoclonal antibodies are employed in clinical practice in advanced colorectal cancer, KRAS mutations have become an important predictor of therapy outcome. Mutational analysis of KRAS was performed on 163 adenocarcinoma samples. Exons 1-3 of KRAS were analyzed using SSCP and sequencing. Fifty seven (35%) carcinomas had missense point mutations in one of codons 12, 13, 59, 61, 117. In accordance with the published data, missense mutations in codons 12 (66%) and 13 (22%) were the most frequent. Mutations in codons 59 and 117 occurred with the same frequency as in codon 61. The only detected insertion occurred in exon 2. 15-bp insertion resulted in tandem duplication of codons 62-66. Presumably, 5 additional amino acids affected switch II conformation and sustained Ras activity due to decreased GTP hydrolysis. We report this unusual new type mutation.

The gain-of-function JAK2 V617F mutation shifts the phenotype of essential thrombocythemia and chronic idiopathic myelofibrosis to more "erythremic" and less "thrombocythemic": a molecular, histologic, and clinical study.

We investigated the prevalence of the JAK2 V617F gain-of-function mutation in patients with Philadelphia chromosome-negative chronic myeloproliferative disorders (Ph- MPD) and explored the links between JAK2 mutational status and the clinicopathologic picture of essential thrombocythemia (ET), chronic idiopathic myelofibrosis (CIMF), and polycythemia vera (PV). Allele-specific polymerase chain reaction results for 59 ET, 18 CIMF, and 9 PV cases were compared with values for clinical variables at presentation and last follow-up and with the diagnostic trephine bone marrow biopsy pictures. JAK2 V617F was found in 38 (64%) of ET cases, 7 (39%) of CIMF cases, and 9 (100%) of PV cases. The ET patients with the mutant JAK2 showed significantly higher (although not overtly polycythemic) red blood cell parameter values, lower platelet counts, and higher white blood cell counts. Similar trends were found in CIMF. Megakaryocyte clustering was much less pronounced in the CIMF cases with mutant JAK2, with an analogous trend occurring in the ET cases. Bone marrow cellularity values and the numbers of CD34+ and CD117+ blasts in the ET and CIMF groups did not differ. Fibrosis was slightly less marked in the ET cases with mutant JAK2. The mutation did not significantly influence the clinical course during the follow-up in either disease in the short term (median follow-up, 22 months). The JAK2 V617F mutation is prevalent in all Ph- MPD and may skew their presenting phenotype, including bone marrow histology, toward a more "erythremic" and less "thrombocythemic" phenotype.

Increased mast cell density in renal interstitium is correlated with relative interstitial volume, serum creatinine and urea especially in diabetic nephropathy but also in primary glomerulonephritis.

In primary glomerulonephritis the degree of interstitial fibrosis governs the renal function. Mast cells participate in renal interstitial fibrosis, but its role remains poorly understood. Some of human mast cells contain chymase and chymase may participate in local angiotensin formation. Material consisted of 35 renal biopsies. The diagnoses included diabetic nephropathy, mesangial glomerulopathy, IgA glomerulopathy and membranous glomerulopathy. Chymase and tryptase-positive cells were stained by immunohistochemistry and counted. Relative interstitial volume (RIV) was measured by point counting method. The density of tryptase-positive cells was 5.26 per 10 high power fields; the density of chymase-positive cells was 2.72. The counts were higher than in controls and highest in diabetic nephropathy. Creatinine serum level was related to density of chymase-positive cells (R = 0.57), density of tryptase-positive cells (R = 0.59) and RIV (R = 0.77). On multiple regression analysis creatinine level was influenced by RIV but also by density of chymase-positive cells. Our findings indicate that both types of mast cells are present in renal interstitium in diabetes and glomerulonephritis, and may influence the renal function. Chymase-positive cells may be more important in this regard.

Immunophenotype and cytogenetics of mucinous tubular and spindle cell carcinoma of the kidney.

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare, recently described entity. The authors present three new cases. The histological picture was that of classic MTSCC, with alternating small tubules located in a mucin-containing stroma, and spindle cell areas composed of bland, monomorphic cells. On immunohistochemistry, the tumors were positive for epithelial markers, including CK7 and CK18, vimentin, CD15, AMACR, and neuroendocrine markers, such as NSE and CD57. On FISH analysis we found losses on chromosomes 1 and 8, and gains of chromosomes 7 and 17. This is the first report of this rare entity in Polish medical literature.

Incidence of lymphomas in Poland. The national register data for 2006.

In Poland, data on the incidence and mortality associated with malignancies are collected by the National Cancer Register (NCR). The Register is based on the International Classification of Diseases (ICD-10), which does not allow for assessing the incidence of lymphatic neoplasms classified according to the WHO classification system enforced since 2001. Under the National Program of Combating Neoplastic Diseases that focuses on detection and diagnosing malignant lymphomas in Poland in order to record and precisely classify lymphatic neoplasms, in 2006, the Haematopathological Section of the Polish Society of Pathologists, acting in collaboration with the Polish Lymphoma Study Group, initiated a nationwide register of lymphatic malignancies, a continuation of the Register of Lymphomas for the Province of Malopolska. The register not only renders epidemiological data more specific, but also allows for a comprehensive quality control.

Gastric solid glomus tumor and multiple glomangiomyomas of the large bowel with intravascular spread, multifocal perivascular proliferations and liver involvement.

The authors present a case of multiple glomus tumors (GTs) of the gastrointestinal tract, representing the type of a gastric glomus tumor proper and large bowel glomangiomyomas with myopericytoma-like features, observed in a 46-year old female, with multifocal perivascular proliferations of primitive cells and hepatic involvement. Histologically, the multilobular gastric tumor and hepatic lesions corresponded to a typical glomus tumor, while the tumor situated in the transverse colon, up to 7 cm in diameter, presented as a glomangiomyoma infiltrative (with myopericytoma-like foci), and satellite tumors in the large bowel mucosa, 0.5-0.7 cm in diameter, represented small glomangiomyomas. In addition, the patient demonstrated two types of concomitant vascular lesions: 1/ intravascular spread in the form of neoplastic plugs that obliterated the lumen of medium-size veins, and 2/ microscopic perivascular proliferation of primitive, small cells seen in the vicinity of the main tumor and in the adjacent adipose tissue. The patient has been ill for 2.5 years; she has been subjected to a partial colectomy with a resection of the small intestinal loop, greater omentum and the right ovary, followed by chemotherapy. At present, she is stable, and the infiltration--especially in the epigastric region--has decreased. The picture may confirm the theory that multiple GTs develop in association with multifocal proliferation of perivascular stem cells, as well as that their ability to penetrate into the lumen of large vessels gives origin to satellite tumors, which are not necessarily metastatic. It seems that at present, the group of perivascular SMA+ tumors may include infantile-type myofibromatosis in adults, myopericytoma, glomangio(myo)pericytoma, glomangiomyoma, glomus tumor proper, and glomangioma. Most likely, also some tumors previously classified as hemangiopericytomas belong to this group. The distinctive feature present in at least some of the above listed perivascular tumors is their synchronous or metachronous growth in a particular region and their ability to occupy intravascular space as nodules or solid bands, which in turn may give origin to satellite tumors. Multifocal lesions associated with a short survival in a given patient will obviously support the presence of metastatic disease. In the remaining cases, determination whether the patient has metastatic disease requires deep consideration and caution, also while deciding on treatment to be employed.

Evaluation of HER2/neu gene amplification in patients with invasive breast carcinoma. Comparison of in situ hybridization methods.

One of the prognostic and predictive factors in invasive breast carcinomas is determination of the HER2/neu proto-oncogene amplification or HER2 protein overexpression. HER2 amplification/overexpression is associated with a more aggressive disease course, greater likelihood of recurrence and generally poor prognosis. The authors compared the specificity, simplicity of a given procedure and method standardization, the simplicity of evaluation the results of each in situ hybridization method and time needed for performing the test. Sixty-three cases of infiltrating breast carcinoma from surgically excised tumors and core needle biopsies were included in the study. The first step was the determination of HER2 status by immunohistochemistry. The patients with moderate (2+) and strong (3+) overexpression of HER2 protein were chosen for determining HER2 amplification by three methods of in situ hybridization: FISH, CISH and in situ hybridization with silver autometallography. The statistical analysis revealed a good agreement between IHC and ISH methods and among ISH methods. The results indicate that all in situ hybridization methods are equivalent tools for evaluating HER2 gene amplification in archival material. There is no clear answer which method is the best assay to determine HER2 marker status, although the authors present some advantages and disadvantages of all the described techniques and a proposed algorithm for choosing a method for a given laboratory.

Immunophenotype of isolated tumour cells in the blood, bone marrow and lymph nodes of patients with gastric cancer.

Immunophenotype of isolated (disseminated or circulating) tumour cells (ITC) in the blood, bone marrow and lymph nodes were studied in patients with gastric cancer. Coexpression of metalloproteinases inducer (EMMPRIN), chemokine receptors (CCR6, CXCR4) and adhesion molecules (Ep-CAM, CD44) was determined on cytokeratin positive (CK+) cells in CD45- cell population sorted out from the blood and/or bone marrow. Eight cytospin samples of blood and 69 samples of bone marrow containing CK+ cells from patients with gastric cancer were included into study. Expression of EMMPRIN and CCR6 were noted in a half of CK+ samples (of blood/bone marrow) whereas the expression of CXCR4 and Ep-CAM was much lower. Analysis of paired data of these determinants expression on CK+ cells showed no association between them. Expression of EMMPRIN, Ep-CAM, CCR6, CCR7, CXCR1, and CXCR4 on ITC in lymph nodes was determined by flow cytometry. In 18 lymph nodes (out of 36 assayed) CK+ cells were found. The expression of CCR6 and Ep-CAM on CK+ cells was observed in almost all studied lymph nodes, CXCR1--in half of them. The expression of EMMPRIN and CCR7 cells was lower. These results suggest that ITC of gastric cancer express variably several molecules that may be involved in metastasis formation.

Predicting kidney function from renal biopsy. Semiquantitative versus quantitative approach.

The term glomerulonephritis encompass a heterogeneous group of diseases; these are a important cause of end stage renal disease. Although several evidence exist, that the main prognostic factors are extraglomerular lesions, no quantitative assessment is usually done. In nephropathological practice a semiquantitative approach is preferred. However, most of work on extraglomerular lesions significance was done with quantitative methods. The aim of the study was to compare the effects of quantitative and semiquantitative assessment of extraglomerular lesions in glomerulonephritis. The material consisted of 120 renal biopsies. On inspection, percentage of sclerosed glomeruli, degree of interstitial fibrosis, degree of interstitial infiltration, degree of tubular atrophy were and degree of mesangial matrix expansion assessed. For quantitative measurements AnalySIS 3.0 pro image analysis system was used. Relative interstitial volume, volume of interstitial infiltrate, with their variability--ross sectional areas of proximal and distal tubules were assessed by point counting method. Relative interstitial volume was significantly correlated to percentage of sclerosed glomeruli (R = 0.33 p < 0.001), degree of tubular atrophy (gamma = 0.57 p < 0.00001), degree interstitial fibrosis (gamma = 0.31 p < 0.0002) and mesangial matrix expansion (gamma = 0.24 p < 0.001). Semiquantitative and quantitative assessment of interstitial infiltrate was significantly correlated as well (gamma = 0.81 p < 0.001). Semiquantitatively assessed degree of tubular atrophy showed significant relation to total proximal tubular area (gamma = -0.30 p = 0,004). Percentage of sclerosed glomeruli was significantly correlated to creatinine level (R = 0.24 p = 0.03), but not to urea level (R = 0.09, NS). Semiquantitatively assessed degree of interstitial fibrosis showed only marginal correlation to creatinine level (gamma = 0.18 NS), however degree of interstitial infiltration was significantly correlated to creatinine (gamma = 0.34 p = 0.002) and urea level (gamma = 0.22 p = 0.06). Degree of tubular atrophy was significantly correlated to creatinine (gamma = 0.43 p < 0.001) and urea level (gamma = 0.28 p = 0.015). Relative interstitial volume was the very most important correlate of creatinine (R = 0.47 p < 0.0001) and urea level (R = 0.30 p < 0.01). In conclusion, it was confirmed, that the strongest correlate of renal function is relative interstitial volume. Some, but not all of semiquantitative parameters are also significantly correlated to kidney function.

Interstitial, tubular and vascular factors in progression of primary glomerulonephritis.

Glomerulonephritis is one of the diseases leading to chronic renal failure and need of renal replacement therapy. Changes in extraglomerular compartments, especially in the interstitium, are thought to play a major role in progression. However, the exact relationships between renal interstitium, tubules and vessels and their prognostic impact are less well understood. The material consisted of 111 biopsies with primary glomerulonephritis. Normal renal tissue from surgically removed kidneys served as controls. Relative interstitial volume (RIV), its variability, volume of interstitial infiltrate, cross-sectional tubular area were measured with the point-counting method. A number of vascular parameters were also measured. The assessed interstitial and tubular parameters were strongly correlated to creatinine level. The strongest correlation was seen for RIV, also on multiple regression. In patients with renal failure, increased RIV, more pronounced vascular lesions and interstitial infiltrates were seen. Survival analysis showed that interstitial expansion is the most important factor leading to renal failure. Tubulointerstitial and vascular factors are interrelated and linked to renal function. RIV has strongest impact on renal function and survival, even taking into account other factors.

[Own experience in treatment of patients with advanced tumours of the paranasal sinuses and the orbit, penetrating to the anterior and medial cranial fossa--preliminary report]. / Wlasne doswiadczenie w leczeniu rozleglych guzów zatok przynosowych i oczodolu zajmujacych struktury przedniego i/lub srodkowego dolu czaszki--doniesienie wstepne.

AIM: Craniofacial resection provides multidirectional approaches to remove nasal and paranasal tumours that involve the skull base. Vital structures, such as the dura, brain, and blood vessels, can be protected or resected and reconstructed safely. An en bloc excision of the tumour can be accomplished. The purpose of this study was to analyse oncological and functional results of craniofacial resection in our series of patients. MATERIAL AND METHODS: The medical records of 40 consecutive patients who had undergone craniofacial resection for tumours of the nasal cavity, paranasal sinuses, and adjacent areas were reviewed. The extent of disease, treatment results (the length of disease-free survival), complications, and prognoses were analysed. RESULTS: Lesions were malignant in 7 patients and benign in the remaining 33. All the patients had dural or intradural involvement. There was no operative death, and the rate of surgical morbidity was 20%. Craniofacial resection is the only surgical approach with acceptable rate of complications in selected patients with tumour comprising the anterior and medial cranial base, nasal cavity, paranasal sinuses, nasopharynx and orbits. Heroic resections are modern surgical procedures challenging both for ENT surgeons and neurosurgeons. The result is satisfactory when they are performed by a multi-specialist team.

Loss of Ku70/Ku80 expression occurs more frequently in hereditary than in sporadic colorectal tumors. Tissue microarray study.

Ku70 and Ku80 proteins take part in the repairing of DNA double-strand breaks by their function as a regulatory subunit of the DNA-dependent protein kinase. In this study, expression of both genes was analyzed in colorectal carcinoma tissue arrays applying immunohistochemistry. Expression of both genes decreased along with pT stage. Significant differences in Ku70 and Ku80 expression were found between pT3 and pT4 as well as between pT2 and pT3 tumors, respectively. Loss of Ku70/Ku80 expression was more frequently observed in hereditary than in sporadic tumors. We conclude that expression of Ku70/Ku80 genes is down-regulated in colorectal carcinoma and that defects of these genes are more frequently observed in hereditary than in sporadic tumors.

Objective, planimetry-based assessment of megakaryocyte histological pictures in Philadelphia-chromosome-negative chronic myeloproliferative disorders: a perspective for a valuable adjunct diagnostic tool.

Philadelphia-chromosome-negative chronic myeloproliferative disorders (Ph- CMPDs)--essential thrombocythemia (ET), chronic idiopathic myelofibrosis (CIMF), and polycythemia vera (PV)--may show clinical and morphological similarities, particularly at the early stages. The differential diagnosis of Ph- CMPDs is important due to their different treatment and prognosis. Cytological features of megakaryocytes are considered valuable in this differentiation. To establish an objective measure of megakaryocyte dysplasia in Ph- CMPDs, we performed computer-assisted morphometry of more than 4,000 cells from 20 cases of ET, 10 of CIMF, 10 of PV, and 10 controls. Megakaryocyte sets from three Ph- CMPDs differed significantly in respect to many planimetric parameters, but not a single shape or size parameter could have been used as a discriminative tool between the entities. However, the discriminant function analysis with the simultaneous assessment of 12 planimetric variables allowed for a proper classification of 20 of 20 ET, 10 of 10 PV, and 9 of 10 CIMF cases based solely on the morphometric features of megakaryocytes. Additionally, we identified certain new patterns of megakaryocytes specific for ET, PV, and CIMF, which, although not dominating in one Ph- CMPD, are unlikely to occur in two others. Objective measurements of megakaryocyte sizes and shapes may assist the diagnosis of Ph- CMPDs.

CDH1 gene promoter hypermethylation in gastric cancer: relationship to Goseki grading, microsatellite instability status, and EBV invasion.

Hypermethylation of the CDH1 promoter region seems to be the most common epigenetic mechanism in this gene silencing in gastric cancer. In this study, CDH1 promoter hypermethylation was observed in 54.8% (46/84) of the analyzed sporadic gastric carcinomas. We introduce a new relation: clustering of Goseki grading into 3 grade was determined by CDH1 promoter hypermethylation. The percentage of methylation in Goseki III cancers was significantly higher (83%) when compared with other grades; the lowest proportion was detected in IV (36%) and II (38%) groups, whereas grade I demonstrated typical percentage of promoter hypermethylation. A novel polymorphism R732R in exon 14 of the CDH1 gene was detected by mutational analysis. Additionally, all cases with the MSI-high phenotype revealed CDH1 promoter hypermethylation. In MSI-low and MSS gastric cancers, this percentage was lower, reaching 71% and 41%, respectively. Moreover, the methylation status was correlated with the LOH phenotype. We detected CDH1 promoter hypermethylation in all EBV-positive gastric cancers (5/5), whereas methylation in the EBV-negative group occurred in 58% of cases. We also report that "methylated" tumors were slightly larger than "nonmethylated," whereas the second group revealed a higher probability of longer patient survival, though these relationships were not statistically significant. These results suggest that downregulation of E-cadherin, caused by promoter hypermethylation, in sporadic gastric carcinomas may be associated with a worse prognosis and specific tumor phenotype.

Clonal lymphocytic populations in Philadelphia-negative chronic myeloproliferative disorders: is the T-cell clonality of 'undetermined' significance (TCUS) linked to a worse clinical outcome?

This study examined the clonality of B- and T-cells by PCR in 83 patients with Philadelphia-negative myeloproliferative disorders (Ph-MPD), to investigate its clinical and morphological correlates. Clonal lymphocytic populations were found in 23% of patients (T: n = 20, B: n = 3), with no frequency differences between ET, CIMF and PV. At the presentation, patients with clonal bands were older (58.1+/-13.8 vs 47.5+/-14.6, p = 0.0039), but did not differ in other clinical parameters. After the median follow-up of 21 months they were less likely to be asymptomatic (11.8% vs 41.1%, p = 0.029). The T-cell clonality was the strongest predictor of the symptomatic last follow-up by discriminant function analysis, surpassing the patient's age. This surprising negative prognostic impact of lymphocyte clonality in Ph-MPD may result from this phenomenon to be a better measure of the 'hematopoietic biologic age' than the metrical age itself.

Analysis of DNA mismatch repair gene expression and mutations in thyroid tumours.

Alterations of DNA mismatch repair genes, primarily demonstrated in hereditary nonpolyposis colorectal carcinomas, were reported to be of relevance for the progression of several sporadic tumours. In this study, the expression and mutations of MLH1, MSH2, PMS1 and PMS2 in a panel of thyroid tumours, including nodular hyperplasia, follicular adenomas and carcinomas, were investigated. The expressions of MLH1, MSH2 and PMS1 were generally higher in malignant tumours than in benign lesions (p < 0.01). This observation can find potential diagnostic application in the differentiation of follicular adenomas from follicullar carcinomas of the thyroid. No point mutations in the DNA mismatch repair genes MSH2 (exon 12, 13) and MLH1 (exon 15, 16) were found.