Epidemiology of malignant breast tumors in the province of Sassari (Sardinia, Italy) in the period 1992-2002

The aim of this study was to evaluate the incidence of malignant breast tumors in the Province of Sassari, Sardinia (Italy) in the period 1992-2002 and to report the variations in comparison to the 1974-1985 period. The analysis of our data showed that the overall number of malignant breast tumors was more than doubled from 1,139 cases in the period 1974-1985 to the 2,735 cases in the period 1992-2002, and the mean rate/100,000 changed from 43.4 to 106.0. The incidence in the age classes 45-64 years, which were at enhanced risk for breast cancer, was globally increased, changing from 143.6/100,000 to 198.7/100,000. On the other hand, the incidence in the youngest age classes (30-34 yrs) was reduced from 59.5% to 27.0%. The analysis of the histotypes showed a relative reduction of ductal carcinoma in the period 1992-2002 in comparison to the previous period 1974-1985 (65.2% vs 82.0%) whereas the incidence of anaplastic forms increased in advanced ages of life. We reported an important reduction of T0 tumors from 3.4% to 0.1%. These data could be due to the low diffusion of screening programs in Sardinia. Tumor metastases were more frequent in advanced age classes. In conclusion, the worrying data of the strong reduction of T0 cases, the increased age of first diagnosis and the advanced forms with positive nodal metastases showed that the prevention program has not been yet well organized.

Epidemiological aspects of ovarian malignancies in North Sardinia in the period 1992-2001

Malignant ovarian tumors have been continuously increasing in Western countries and represent the leading cause of death for gynecological cancer. In fact, the mortality for malignant ovarian tumors remains very high with a low percentage of 5-year survival in the advanced stage of disease. The aim of this study was to evaluate the incidence trend and epidemiological characteristics of malignant ovarian tumors in the Province of Sassari, Sardinia (Italy) in the period 1992-2001 and to report the variations in comparison to the 1974-1985 period. The analysis of our data regarding the period 1992-2001, if compared with those of the period 1974-85, showed an increase of malignant ovarian tumors which triplicated achieving an incidence of 11.99/100,000 vs 4.27/100,000. The analysis of our epidemiologic data showed an increase of the age of first diagnosis (mean 60.9 years for epithelial ovarian tumors), the occurrence of the cancer in women at low socio-economic levels and a family history of cancer among the patients with malignant ovarian tumors. These data suggest that both local environmental factors combined with genetic characteristics play a role in the pathogenesis of ovarian tumors. The genetic characteristics could be of particular interest because Sardinia has been through the centuries a geographical area with little population migration. The marked increase in the incidence of ovarian tumors in the last several years points out the need to organize systematic screening by ultrasonography in our population.

Overexpression of h-prune in Breast Cancer is Correlated with Advanced Disease Status

Purpose: The h-prune gene is involved in cellular motility and metastasis formation in breast cancer through interacting with the nm23-H1 protein. The aim of this study was to better define the clinical and pathologic role of h-prune in breast cancer patients.

Experimental Design: Using immunohistochemistry, we assessed h-prune and nm23-H1 protein expression in two series of breast cancer patients: (i) in 2,109 cases with pathologic reports on primary tumors and (ii) in 412 cases with detailed clinical information. To assess the role of DNA amplification in gene activation, the h-prune copy number was evaluated by fluorescence in situ hybridization analysis in 1,016 breast cancer cases.

Results: In the patients tested (n = 2,463), 1,340 (54%) had an increased level of h-prune expression; a positive immunostaining for nm23-H1 was observed in 615 of 2,061 (30%) cases. Overexpression of h-prune was associated with multiple gene copy number at chromosome 1q21.3 in a very limited fraction of cases (68 of 1,016; 6.7%), strongly indicating that alternative pathways induce h-prune activation in breast cancer. Multivariate Cox regression analysis showed that neither h-prune overexpression nor decreased nm23-H1 immunostaining is independent prognostic factors. However, a significant association of h-prune overexpression with either advanced lymph node status (P = 0.017) or presence of distant metastases (P = 0.029) was observed.

Conclusions: Although not significantly correlated with overall survival, positive h-prune immunostaining identifies subsets of breast cancer patients with higher tumor aggressiveness. Further investigations using larger collections of advanced breast cancer patients are required for assessing the predictive role of h-prune in breast cancer.

Overexpression of h-prune in breast cancer is correlated with advanced disease status

PURPOSE

The h-prune gene is involved in cellular motility and metastasis formation in breast cancer through interacting with the nm23-H1 protein. The aim of this study was to better define the clinical and pathologic role of h-prune in breast cancer patients.

EXPERIMENTAL DESIGN

Using immunohistochemistry, we assessed h-prune and nm23-H1 protein expression in two series of breast cancer patients: (i) in 2,109 cases with pathologic reports on primary tumors and (ii) in 412 cases with detailed clinical information. To assess the role of DNA amplification in gene activation, the h-prune copy number was evaluated by fluorescence in situ hybridization analysis in 1,016 breast cancer cases.

RESULTS

In the patients tested (n = 2,463), 1,340 (54%) had an increased level of h-prune expression; a positive immunostaining for nm23-H1 was observed in 615 of 2,061 (30%) cases. Overexpression of h-prune was associated with multiple gene copy number at chromosome 1q21.3 in a very limited fraction of cases (68 of 1,016; 6.7%), strongly indicating that alternative pathways induce h-prune activation in breast cancer. Multivariate Cox regression analysis showed that neither h-prune overexpression nor decreased nm23-H1 immunostaining is independent prognostic factors. However, a significant association of h-prune overexpression with either advanced lymph node status (P = 0.017) or presence of distant metastases (P = 0.029) was observed.

CONCLUSIONS

Although not significantly correlated with overall survival, positive h-prune immunostaining identifies subsets of breast cancer patients with higher tumor aggressiveness. Further investigations using larger collections of advanced breast cancer patients are required for assessing the predictive role of h-prune in breast cancer.

Identification of a novel candidate gene,CASC2, in a region of common allelic loss at chromosome 10q26 in human endometrial cancer

Allelic deletions, which are suggestive for the presence of tumor suppressor genes, represent a common event in endometrial cancer (EC). Previous loss-of-heterozygosity studies for human chromosome 10q identified a candidate deletion interval at 10q25-q26, which we further narrowed to a 160-kb region at 10q26, bounded by markers D10S1236 and WIAF3299. Using a positional candidate approach, we identified three alternative transcripts of a novel human gene, CASC2 (cancer susceptibility candidate 2; formely C10orf5). One of such transcripts, CASC2a, encodes a short protein of 102 amino acids with no similarity to any other known gene product. Three (7%) CASC2a mutations were identified in tumor DNA from 44 EC patients. While c.-156G>T and c.22C>T (p.Pro8Ser) are sequence variants with unknown functional significance, c.84delA is a mutation with a truncation effect on the predicted protein (p. Asn28fsX50). Expression studies by real-time RT-PCR on several normal and tumor cells revealed that CASC2a mRNA is downregulated in cancer, suggesting that it may act as a potential tumor suppressor gene. The very low mutation rate seems to also indicate that inactivation of CASC2a might probably be due to mechanisms different from genetic alterations.

Microsatellite instability and mutation analysis among southern Italian patients with colorectal carcinoma: detection of different alterations accounting for MLH1 and MSH2 inactivation in familial cases

BACKGROUND

Microsatellite instability (MSI) is due to defective DNA mismatch repair (MMR) and has been detected at various rates in colorectal carcinoma (CRC). The role of MSI in colorectal tumorigenesis was assessed further in this study by both microsatellite analysis of two CRC subsets [unselected patients (n = 215) and patients <50 years of age (n = 95)], and mutation screening of the two major MMR genes MLH1 and MSH2 among familial CRC cases.

PATIENTS AND METHODS

PCR-based microsatellite analysis was performed on paraffin-embedded tissues. In CRC families, MLH1/MSH2 mutation analysis and MLH1/MSH2 immunostaining were performed on germline DNA and MSI+ tumour tissues, respectively.

RESULTS

The MSI+ phenotype was detected in 75 (24%) patients, with higher incidence in early-onset or proximally located tumours. Among 220 patients investigated for family cancer history, MSI frequency was markedly higher in familial [18/27 (67%)] than in sporadic [32/193 (17%)] cases. Three MLH1 and six MSH2 germline mutations were identified in 14 out of 36 (39%) CRC families. Prevalence of MLH1/MSH2 mutations in CRC families was significantly increased by the presence of: (i) fulfilled Amsterdam criteria; (ii) four or more CRCs; or (iii) one or more endometrial cancer. While MSH2 was found mostly mutated, almost all [8/9 (89%)] familial MSI+ cases with loss of the MLH1 protein were negative for MLH1 germline mutations.

CONCLUSIONS

Both genetic (for MSH2) and gene-silencing (for MLH1) alterations seem to be involved in CRC pathogenesis.

BRAF gene is somatically mutated but does not make a major contribution to malignant melanoma susceptibility: the Italian Melanoma Intergroup Study

PURPOSE

Ocogenic activation of the BRAF gene has been demonstrated to be involved in the pathogenesis of malignant melanoma (MM). In this study, we investigated the contribution of BRAF to melanoma susceptibility, also making a comparison with frequency of CDKN2A germline mutations in MM patients from different areas in Italy.

PATIENTS AND METHODS

sing a combination of denaturing high-performance liquid chromatography analysis and automated sequencing on genomic DNA from peripheral blood or tumor tissue samples, 569 MM patients (211 from northern Italy and 358 from southern Italy) were screened for BRAF mutations.

RESULTS

Three BRAF germline sequence variants (M116R, V599E, and G608H) were identified in four (0.7%) of 569 MM patients. The most common BRAF mutation, V599E, was detected in one germline DNA sample only; M116R and G608H were newly described mutations. A high frequency (59%) of BRAF mutations was instead observed in tumor samples from patients also undergoing germline DNA analysis; at the somatic level, substitution of valine 599 was found to account for the majority (88%) of BRAF mutations. We then estimated the germline mutation rates in BRAF and CDKN2A among 358 consecutively collected patient samples originating in southern Italy; a low (2.5%) or very low (0.29%) prevalence of CDKN2A and BRAF mutations, respectively, was detected.

CONCLUSION

utation analysis of either blood DNA from a large collection of MM patients or matched MM tissues from a subset of such patients revealed that BRAF is somatically mutated and does not play a major role in melanoma susceptibility. The present study further suggests that patient origin may account for different mutation rates in candidate genes.

The incidence of female genital tumors in the Province of Sassari in the period 1992-2000

The incidence of gynecologic tumors in the Province of Sassari in the period 1992-2000 has been studied in order to estimate their value and to make a comparison with the data of the period 1974-83. The analysis of our data regarding the period 1992-2000, if compared with those of the previous period 1974-83, showed a change in the percentage distribution of all gynecologic tumors, with an increase in the incidence of malignant tumors of the ovary (from 17.1% to 28.0%) and a reduction in the incidence of endometrial carcinoma (from 52.1% to 45.0%). Cervix cancer seemed stationary with a mild reduction (from 26.8% to 23.0%). The data showed, with regard to the incidence per 100,000, an increase of endometrial carcinoma (19.05 per 100,000 vs 11.99 per 100,000) and malignant ovarian tumor (11.99 per 100,000 vs 3.95 per 100,000). Our data reported a worrying increase of hormonal-dependent tumors in North Sardinia such as endometrial and ovarian cancer with the highest increase in malignant ovarian tumors. In comparison to the previous period we confirmed a historically low incidence of cervical and external genitalia tumors (vulva and vagina) in North Sardinia.

Mutation analysis of candidate genes in melanoma-prone families

Putative tumour suppressor genes CDKN2A and CDKN2B (on chromosome 9p21) and CDKN2A-interacting cell growth regulatory genes CDK4 and Id-1 have been demonstrated to be involved in the pathogenesis of malignant melanoma (MM). Mutation analysis of these candidate genes was performed in MM families from southern Italy with three or more affected members or two affected members and one or more relative with histologically diagnosed atypical naevus. Two CDKN2A mutations, Arg24Pro and 1-292 G>A, were observed in two (15%) families; except for CDKN2A and Id-1 polymorphisms, no sequence variations were detected in the remaining genes. Screening among 119 sporadic MM cases revealed two additional CDKN2A mutations at very low prevalences. Identification of a large shared haplotype at 9p21 in some MM families negative for CDKN germline mutations suggests that other CDKN-inactivating mechanisms may be responsible for MM predisposition or, alternatively, additional susceptibility gene(s) may be present on chromosome 9p21. Fluorescence in situ hybridization analysis of a subset of MM tissue sections seemed to indicate that the D9S171 locus may be involved in MM pathogenesis.

High-resolution methylation analysis of the hMLH1 promoter in sporadic endometrial and colorectal carcinomas

BACKGROUND

Microsatellite instability (MSI) has been reported in endometrial carcinoma (EC) and in colorectal carcinoma (CRC), primarily as a result of defective DNA mismatch repair (MMR). The MMR gene hMLH1 commonly is inactivated in both EC and CRC. In the current study, epigenetic mechanisms involved in hMLH1 inactivation have been investigated to further elucidate the role of these mechanisms in the pathogenesis of EC and CRC.

METHODS

Polymerase chain reaction (PCR)-based microsatellite analysis performed on paraffin-embedded tissues was used to select 42 sporadic carcinomas (21 ECs and 21 CRCs) with MSI. Immunohistochemistry (IHC), using the anti-hMLH1 antibody, and mutation analysis, using denaturing high-performance liquid chromatography and automated sequencing, were performed on unstable carcinoma samples. Methylation analysis, using modified protocols for bisulfite treatment and methylation-specific PCR (MSP), was performed on DNA from archival tissue samples.

RESULTS

No MSI-positive tumor samples with normal hMLH1 immunostaining (n = 7) exhibited hMLH1 promoter methylation, whereas 8 of 35 unstable cases with loss of hMLH1 expression (23%) exhibited MSP amplification. Among analyzed cases, germ-line mutations of hMLH1 were found in 4 of 20 unmethylated samples (20%) and in 0 of 8 methylated samples. Bisulfite sequencing of amplification products from methylated samples demonstrated that almost all CpG dinucleotides within the hMLH1 promoter elements underwent methylation.

CONCLUSIONS

Although an MMR gene other than hMLH1 may be responsible for genetic instability in MSI-positive/IHC-positive tumors, the presence of MSP amplification and allelic deletions within the hMLH1 locus in subsets of MSI-positive/IHC-negative cases strongly suggests that hMLH1 promoter methylation may contribute to the inactivation of both hMLH1 alleles. Bisulfite analysis suggests that the mechanisms of hMLH1 silencing may depend on CpG density rather than site-specific methylation. Cancer 2003;98:1540-6.

A case of adult-onset tubulointerstitial nephritis and uveitis ("TINU syndrome") associated with sacroileitis and Epstein-Barr virus infection with good spontaneous outcome

The authors report a case of tubulointerstitial nephritis and uveitis (TINU syndrome) in a 48-year-old woman. The patient's ocular symptoms (relapsing bilateral uveitis) began 4 months before the renal disease was diagnosed and were treated successfully with local steroid therapy. The main baseline laboratory findings were anemia, a rapid sedimentation rate, and a decreased renal function. Urinalysis results showed mild proteinuria and some hyaline and hyaline-granular casts. Immunoglobulin (Ig) G and IgM antibodies to Epstein-Barr virus (EBV) were present. The renal biopsy showed interstitial lymphocytes and infiltration by rare plasma cells, tubular atrophy without granulomas, and slight expansion of the mesangium; electronic microscopy showed rare electron-dense deposits in the mesangium; no vascular alterations were seen, and immunofluorescent staining was uniformly negative. X-ray of the pelvis showed bilateral sacroileitis, which has been previously described in only 1 case of TINU syndrome; human leukocyte antigen B27 was negative. After 6 months without any therapy, all laboratory findings were normal; after 30 months, renal function was still normal, uveitis had not relapsed, but sacroiliac involvement was still present; EBV-viral capsid antigen (VCA) IgM were still high (28 UA/mL), and the EBV IgG titers were increased (VCA>170, EBV-nuclear antigen 108 UA/mL). This case confirms that this rare entity, originally observed in children, may occur and have a favorable spontaneous renal outcome also in the adult; EBV may play a role, as previously suggested. This is, to the authors' knowledge, the first reported case of TINU syndrome with the association of a well-documented bilateral sacroileitis.

The role of (99m)Tc-tetrofosmin pinhole-SPECT in breast cancer non palpable axillary lymph node metastases detection

AIM

We evaluated the usefulness of (99m)Tc-tetrofosmin axillary pinhole (P)-SPECT in breast cancer (BC) non palpable axillary lymph node metastasis detection compared with conventional planar and SPECT scintimammography.

METHODS

We studied prospectively 188 consecutive patients with suspected primary BC, negative at axillary clinical examination. Ten minutes after 740 MBq (99m)Tc-tetrofosmin injection, planar and SPECT scintimammography were acquired, followed by axillary P-SPECT imaging.

RESULTS

At histology, 12 patients had benign mammary lesions and 176 had BC. Axillary lymph node dissection (ALND) was performed in all BC patients, bilaterally in 3 cases: 74/179 axillae had metastases. P-SPECT showed a significantly higher overall sensitivity than SPECT and planar (93.2% vs 85.1% and 36.5%, respectively; p<0.05 and p<0.0005, respectively) and was false negative in 5 patients with 1 metastatic node each, micrometastatic in 4/5 cases; SPECT and planar were also false negative in these 5 cases and in 6 and in 42 further cases, respectively. P-SPECT added important prognostic information by distinguishing single from multiple and pound 3 from >3 nodes; only P-SPECT defined the exact number of nodes in 15/25 patients with 2-4 nodes. P-SPECT showed the highest accuracy and NPV: 92.7% and 95%, respectively (SPECT 90.5% and 90%, respectively; planar 73.2% and 68.9%, respectively).

CONCLUSION

(99m)Tc-tetrofosmin axillary P-SPECT appears highly accurate in BC non palpable axillary lymph node metastasis detection and significantly more sensitive than both planar and SPECT, its few false negative results predominantly concerning micrometastases; moreover, only P-SPECT gave additional important prognostic information. Given its very high NPV, P-SPECT could also be used to better select patients who might avoid ALND.

Assessment of genetic instability in melanocytic skin lesions through microsatellite analysis of benign naevi, dysplastic naevi, and primary melanomas and their metastases

Microsatellite instability (MSI) is caused by replication errors due to deficient DNA mismatch repair and has been associated with tumour progression in various types of cancer. Controversial results have been reported concerning the frequency and significance of MSI in malignant melanoma. In this study, the time of onset and relative incidence of MSI were determined during the progression of melanocytic tumours, starting with benign melanocytic naevi. MSI was studied at 13 loci containing single, di- or trinucleotide repeat sequences and mapping to five different chromosomal locations. Tumours were classified as being low frequency MSI (L-MSI+) or high frequency MSI (H-MSI+) when either one or at least two marker loci, respectively, displayed mutant alleles in tumour DNA compared with the corresponding normal tissue DNA. None of the eight melanocytic naevi studied showed MSI, whereas a moderate frequency of H-MSI was detected in dysplastic naevi (one out of 11; 9%) and primary melanomas (six out of 56; 11%). The incidence of H-MSI was increased in melanoma metastases from the same patients (nine out of 42; 21%). In contrast to previously reported data showing higher rates of MSI in melanoma, genetic instability seems to be present in a minority of malignant melanoma lesions. However, our findings are consistent with the hypothesis that MSI may be sequentially induced during malignant evolution, contributing to the progression of a subset of melanocytic tumours.

X-inactivation patch size in human female tissue confounds the assessment of tumor clonality

Most models of tumorigenesis assume that tumors are monoclonal in origin. This conclusion is based largely on studies using X chromosome-linked markers in females. One important factor, often ignored in such studies, is the distribution of X-inactivated cells in tissues. Because lyonization occurs early in development, many of the progeny of a single embryonic stem cell are grouped together in the adult, forming patches. As polyclonality can be demonstrated only at the borders of X-inactivation patches, the patch size is crucial in determining the chance of demonstrating polyclonality and hence the number of tumors that need to be examined to exclude polyclonality. Previously studies using X-linked genes such as glucose-6-phosphate dehydrogenase have been handicapped by the need to destroy the tissues to study the haplotypes of glucose-6-phosphate dehydrogenase [Fialkow, P.-J. (1976) Biochim. Biophys. Acta 458, 283-321] or to determine the restriction fragment length polymorphisms of X chromosome-linked genes [Vogelstein, B., Fearon, E. R., Hamilton, S. R. & Feinberg, A. P. (1985) Science 227, 642-645]. Here we visualize X-inactivation patches in human females directly. Results show that the patch size is relatively large in both the human colon and breast, confounding assessment of tumor clonality with traditional X-inactivation studies.

Prognostic value of circulating melanoma cells detected by reverse transcriptase-polymerase chain reaction

PURPOSE

Factors that are predictive of prognosis in patients who are diagnosed with malignant melanoma (MM) are widely awaited. Detection of circulating melanoma cells (CMCs) by reverse transcriptase-polymerase chain reaction (RT-PCR) has recently been postulated as a possible negative prognostic factor. Two main questions were addressed: first, whether the presence of CMCs, defined as the patient being positive for any of the three markers, had a prognostic role; and second, what the predictive value of each individual marker was.

PATIENTS AND METHODS

A consecutive series of 200 melanoma patients observed between January 1997 and December 1997, with stage of disease ranging from I to IV, was analyzed by semiquantitative RT-PCR. Tyrosinase, p97, and MelanA/MART1 were used as markers to CMCs on baseline peripheral blood samples. Progression-free survival (PFS) was used as a unique end point and was described by the product limit method. Multivariable analysis was applied to verify whether the auspicated prognostic value of these markers was independent of the stage of disease, and a subgroup analysis was performed that excluded patients with stage IV disease.

RESULTS

Overall, 32% (64 of 200) of patients progressed, and a median PFS of 52 months in the whole series was observed. The presence of CMCs and the markers individually or combined was predictive of prognosis in the univariate analysis but did not provide additional prognostic information to the stage of disease in multivariable models. In the subgroup analysis of stage (ie, I-III subgroup), similar results were observed.

CONCLUSION

Detection of CMCs in peripheral blood samples at the time of MM diagnosis by semiquantitative RT-PCR does not add any significant predictive value to the stage of disease. Thus, this approach should not be used in clinical practice, and further studies are required to determine its usefulness.

BRCA1 and BRCA2 germline mutations in Sardinian breast cancer families and their implications for genetic counseling

BACKGROUND

The Sardinian population is genetically homogeneous and could be useful in understanding better the genetics of a complex disease like breast cancer (BC).

PATIENTS AND METHODS

Using a screening assay based on a combination of single-strand conformation polymorphism, denaturing high-performance liquid chromatography and sequence analysis, 47 Sardinian families with three or more BC cases were screened for germline mutations in BRCA1 and BRCA2 genes.

RESULTS

Three BRCA1/2 germline sequence variants were identified. While BRCA2-Ile3412Val is a missense variant with unknown functional significance, BRCA2-8765delAG and BRCA1-Lys505ter are two deleterious mutations (due to their predicted effects on protein truncation), which were found in seven families (15%). BRCA2-8765delAG was found in six of eight (75%) BRCA1/2-positive families and seven of 501 (1.4%) unselected and consecutively collected BC patients. Prevalence of BRCA1/2 mutations in BC families was significantly correlated with the total number of female BCs (P <0.01) and increased by the presence of (i) at least one case of ovarian or male BC, or (ii) three generations affected, or (iii) bilateral BC.

CONCLUSIONS

Identification of such features should address BC patients and their families to genetic counseling and BRCA1/2 mutational analysis. In addition, this is the first report of a detailed BRCA1/2 mutation screening in Sardinia, having immediate implications for the clinical management of BC families.

Chromosomal abnormalities and microsatellite instability in sporadic endometrial cancer

Defective DNA mismatch repair and nonfunctional mechanisms controlling the proper progression of the cell cycle have been proposed as being responsible for the genomic instability and accumulation of karyotypic alterations in endometrial cancer (EC). To assess whether numerical chromosomal anomalies (aneuploidy) and microsatellite instability (MSI) might be representative of distinctive tumour behaviour, paraffin-embedded tissue samples from 86 patients with sporadic EC were evaluated by both fluorescence in situ hybridisation (FISH) and microsatellite analysis, using free nuclei and genomic DNAs (respectively). Approximately one-third of the tumours analysed (24/74; 32%) exhibited MSI, whereas 38/86 (44%) of the EC samples displayed aneuploidy. The majority of the unstable cases (15/24; 63%) were from advanced-stage patients. Conversely, 23 (61%) out of the 38 tumours with aneuploidy were from early-stage patients. No apparent correlation was found between MSI and aneuploidy, whereas the immunohistochemical (IHC) analysis revealed that inactivation of the MLH1 mismatch repair gene may be involved in the majority of the MSI+ sporadic ECs. No genetic or cytogenetic alteration analysed here seems to add any significant predictive value to the stage of disease.

Prevalence and prognostic role of microsatellite instability in patients with rectal carcinoma

BACKGROUND

Association between microsatellite instability (MSI) and favorable postoperative survival in patients with colorectal cancer receiving adjuvant chemotherapy has been indicated. To evaluate whether an analogous positive prognostic role of MSI could be present in rectal carcinoma (RC; most RC patients receive adjuvant radiotherapy), PCR-based microsatellite analysis of archival RCs and statistical correlation with clinico-pathological parameters were performed.

PATIENTS AND METHODS

DNA from paraffin-embedded paired samples of tumors and corresponding normal tissue from 91 RC patients was analyzed for MSI using five microsatellite markers (tumors were classified as MSI(+) when two or more markers were unstable).

RESULTS

Seventeen (19%) RC patients exhibited a MSI(+) phenotype. Prevalence of instability was found in patients with earlier RC onset (28% in cases with diagnosis age < or =55 years versus 15% in cases >55 years), whereas similar MSI frequencies were observed in patients with different disease stage or receiving different adjuvant therapies. While MSI was detected in seven (64%) of 11 familial patients, a remarkably lower MSI incidence was observed in sporadic cases (10/80; 12.5%). A significant association with better disease-free survival (DFS) and overall survival (OS) was found for MSI(+) patients (median DFS/OS, 30/32 months) in comparison to MSI(-) ones (median DFS/OS, 18/21 months) (P <0.001).

CONCLUSIONS

MSI was demonstrated to be a strong molecular prognostic marker in rectal carcinoma, independent of the administered treatment (radiotherapy, chemotherapy or both).

Microsatellite instability and mutation analysis of candidate genes in unselected sardinian patients with endometrial carcinoma

BACKGROUND

Microsatellite instability (MSI) is due mostly to a defective DNA mismatch repair (MMR). Inactivation of the two principal MMR genes, hMLH1 and hMSH2, and the PTEN tumor suppressor gene seems to be involved in endometrial tumorigenesis. In this study, Sardinian patients with endometrial carcinoma (EC) were analyzed to assess the prevalence of both the mutator phenotype (as defined by the presence of MSI and abnormal MMR gene expression at the somatic level) and the hMLH1, hMSH2, and PTEN germline mutations among patients with MSI positive EC.

METHODS

Paraffin embedded tissue samples from 116 consecutive patients with EC were screened for MSI by polymerase chain reaction-based microsatellite analysis. Immunohistochemistry (IHC) with anti-hMLH1 and anti-hMSH2 antibodies was performed on MSI positive tumor tissue sections. Germline DNA was used for mutational screening by denaturing high-performance liquid chromatography analysis and automated sequencing.

RESULTS

Thirty-nine patients with EC (34%) exhibited MSI; among them, 25 tumor samples (64%) showed negative immunostaining for hMLH1/hMSH2 proteins (referred to as IHC negative). No disease-causing mutation within the coding sequences of the hMLH1/hMSH2 and PTEN genes was found in patients with EC who had the mutator phenotype (MSI positive and IHC negative), except for a newly described hMLH1 missense mutation, Ile655Val, that was observed in 1 of 27 patients (4%). Although MSI was more common among patients with advanced-stage EC and increased as the tumor grade increased, no significant correlation with disease free survival or overall survival was observed among the two groups (MSI positive or MSI negative) of patients with EC.

CONCLUSIONS

In patients with MSI positive EC, epigenetic inactivations rather than genetic mutations of the MMR genes seem to be involved in endometrial tumorigenesis. No prognostic value was demonstrated for MSI in patients with EC.

Identification of Mycobacterium avium subsp. paratuberculosis in biopsy specimens from patients with Crohn's disease identified by in situ hybridization

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract of unknown etiology. We report on the presence of cell wall-deficient Mycobacterium avium subsp. paratuberculosis in 35 of 48 paraffin-embedded tissue specimens from 33 patients with Crohn's disease by in situ hybridization with IS900 as a probe.