Andréa Rodrigues Cordovil Pires

TMA for all: a new method for the construction of tissue microarrays without recipient paraffin block using custom-built needles

BackgroundTMAs are becoming a useful tool for research and quality control methods, mostly for immunohistochemistry and in situ hybridization.MethodsA new technique that allows building TMA blocks with more than 300 tissue cores without using a recipient paraffin block for the tissue cores and without using a commercial TMA builder instrument is described. This technique is based on the construction of TMA needles modifying conventional hypodermic needles to punch tissue cores from donor blocks, which are attached by double-side adhesive tape on a computer-generated paper grid used to align the cores on the block mould, which is filled with liquid paraffin.ResultsMore than two hundred TMA blocks were constructed using this method, utilized in immunohistochemistry and histochemistry as positive and negative controls and also in research.ConclusionThis technique has the following advantages: it is easy to reproduce, affordable, quick and creates uniform blocks with more than 300 cores aligned, adherent and easy to cut, with negligible losses during cutting and immunohistochemistry and in situ hybridization procedures.

The benefits of using selenium in the treatment of Chagas disease: prevention of right ventricle chamber dilatation and reversion of Trypanosoma cruzi-induced acute and chronic cardiomyopathy in mice

Cardiac damage is a frequent manifestation of Chagas disease, which is caused by the parasite Trypanosoma cruzi. Selenium (Se) is an essential micronutrient, the deficiency of which has been implicated in the development of cardiomyopathy. Our group has previously demonstrated that Se supplementation prevents myocardial damage during acute T. cruzi infection in mice. In this study, we analyzed the effect of Se treatment in cases of T. cruzi infection using prevention and reversion schemes. In the Se prevention scheme, mice were given Se supplements (2 ppm) starting two weeks prior to inoculation with T. cruzi(Brazil strain) and continuing until 120 days post-infection (dpi). In the Se reversion scheme, mice were treated with Se (4 ppm) for 100 days, starting at 160 dpi. Dilatation of the right ventricle was observed in the infected control group at both phases of T. cruzi infection, but it was not observed in the infected group that received Se treatment. Surviving infected mice that were submitted to the Se reversion scheme presented normal P wave values and reduced inflammation of the pericardium. These data indicate that Se treatment prevents right ventricular chamber increase and thus can be proposed as an adjuvant therapy for cardiac alterations already established by T. cruzi infection.

Cell-cycle and suppressor proteins expression in uterine cervix in HIV/HPV co-infection: comparative study by tissue micro-array (TMA)

BackgroundThe oncoproteins of human papillomavirus (HPVs) directly effect cell-cycle control. We hypothesize that regulatory and cell cycle protein expression might be additionally modified in the cervix of HIV/HPV co-infected women.MethodsWe analyzed the expression of Rb, p27, VEGF and Elf-1 transcriptor factor by immunohistochemistry in 163 paraffin-embeded cervical samples using Tissue Micro-Array (TMA) and correlated this to HIV-1 and HPV infection.ResultsHIV/HPV co-infection was associated with a significant increase in expression (p < 0.001) of VEGF and p27 in both low and high grade CIN when compared to the cervices of women infected by HPV alone. Decreased Rb expression was evident with increased CIN grade in the cervices of women infected with HPV alone (p = 0.003 average of cells/mm2 in CIN I: 17.9, CIN II/III: 4.8, and tumor 3.9). Rb expression increased 3-fold for both low and high grade CIN with HPV/HIV-1 co-infection compared to HPV infection alone but did not reach statistical significance. There was a significant increase in Elf-1 expression in HPV+/HIV- women with CIN II/III and tumor (average of cells/mm2 in CIN I: 63.8; CIN II/III: 115.7 and tumor: 112.0, p = 0.005), in comparison to controls.ConclusionCo-infection of HPV and HIV leads to significant increase in the VEGF and p27 expression when compared to HPV+/HIV-negative infection that could facilitate viral persistence and invasive tumor development.

Malignant peripheral nerve sheath tumors: clinicopathological aspects, expression of p53 and survival

Malignant peripheral nerve sheath tumors (MPNSTs) arerare and highly aggressive neoplasms, representing only 5%of soft tissue sarcomas (1,2). Approximately half of MPNSTcases occur in association with neurofibromatosis type 1(NF1) (3). MPNSTs may appear de novo or develop from themalignant transformation of a benign neural neoplasm,generally a plexiform neurofibroma (1). Solitary (unasso-ciated with NF1) and localized (or discrete; multiple in NF1)neurofibromas do not have malignant transformationpotential (1,3). NF1 loss of heterozygosity (LOH) has beendemonstrated in NF1-associated and sporadic MPNSTs.Although NF1 LOH is believed to be sufficient for neu-rofibroma development, MPNST pathogenesis has beensuggested to be a multistage process that includes othermolecular alterations (4,5). TP53 mutations have been foundin a subgroup of MPNSTs, indicating that a p53-mediatedpathway is involved in their development (5,6).Some clinicopathological features (e.g., the presence ofNF1,high histologicalgrade,necrosis,andrhabdomyoblasticdifferentiation) have been indicated to be important factorsforlower survival in MPNST cases in some studies butnotinothers (2,7–10). The clinical significance of p53 expression inMPNSTs is also a controversial issue. We aimed to study p53expression in MPNSTs and investigate its impact, as well astheimpactsoftheclinicopathologicalfeaturesofMPNSTs,onthe survival rates. We also compared p53 expression inMPNSTswith theirclinicopathological features and with p53expression in neurofibromas.

An evaluation of p16INK4a expression in cervical intraepithelial neoplasia specimens, including women with HIV-1

Although several studies have evaluated the role of p16(INK4a) as a diagnostic marker of cervical intraepithelial neoplasia (CIN) and its association with disease progression, studies regarding the role of p16(INK4a) in human immunodeficiency virus (HIV)-infected patients remain scarce. The present study was designed to determine the potential utility of p16(INK4a) as a diagnostic marker for CIN and invasive cervical cancer in HIV-positive and negative cervical specimens. An immunohistochemical analysis of p16(INK4a) was performed in 326 cervical tissue microarray specimens. Performance indicators were calculated and compared using receiving operating characteristics curve (ROC)/area under the curve. In HIV-1-negative women, the percentage of cells that was positive for p16(INK4a) expression was significantly correlated with the severity of CIN (p < 0.0001). A ROC curve with a cut-off value of 55.28% resulted in a sensitivity of 89%, a specificity of 81%, a positive predictive value of 91% and a negative predictive value of 78%. HIV-seropositive women exhibited decreased expression of p16(INK4a) in CIN2-3 specimens compared with HIV-negative specimens (p = 0.031). The ROC data underscore the potential utility of p16(INK4a) under defined conditions as a diagnostic marker for CIN 2-3 staging and invasive cervical cancer. HIV-1 infection, however, is associated with relatively reduced p16(INK4a) expression in CIN 2-3.

Dengue infection in pregnancy and its impact on the placenta

A histopathological and immunohistochemical study was conducted in placental tissues and retained products of conception from 24 patients with confirmed dengue infection during pregnancy. The immunohistochemical assay was positive for dengue virus in 19 placental and three ovular remnants analyzed. The light microscopic findings were signs of hypoxia, choriodeciduitis, deciduitis and intervillositis and the viral antigens were found in cytoplasmic of the trophoblast, villous stroma and decidua. Our results suggest that immunohistochemistry could be used as a laboratory confirmation method for dengue in pregnant women, especially in endemic areas when embedded material is the only material available.

A Comparative Analysis of Clinical and Molecular Factors with the Stage of Cervical Cancer in a Brazilian Cohort

Cell cycle protein expression plays an important role in the pathophysiology of cervical cancer. However, few studies have attempted to correlate the use of these biomarkers with the clinical progression of the tumor. Objectives 1) To analyze the expression of Ki-67, p53 and p16INK4a in cervical cancer, 2) to correlate the relative expression of these proteins as well as clinical parameters with the stage of disease, and 3) to determine the HPV DNA prevalence and subtype distribution. Methods Tissue Micro-Arrays (TMA) from patients with invasive cervical cancer (ICC) and controls were analyzed. HPV DNA detection was done by PCR and in situ hybridization. Ki-67, p53 and p16INK4a were analyzed by immunohistochemistry; clinical data was derived from the chart review. Results Advanced tumor stage (III and IV) was strongly associated (p<0.005) with advanced age (>55 years old), with more than four pregnancies and with the lack of formal education. HPV DNA was found in 94.3% of cases with the most prevalent types being HPV16 (67.5%), followed by HPV33 (12.0%) and HPV35 (3.6%). High expression of Ki-67 and p16 was more common in the advanced FIGO stages (p = 0.023). Women with HPV16 tended to be younger (50.9 years; SE 1.9) compared to women with other types (59.9 years; SE 2.8). Conclusion We found that Ki-67 and p16 expression were independently associated with the tumor stage. We also noted that about 1/3 of the cervical cancers in this Brazilian cohort were not associated with HPV types directly targeted by the current HPV vaccines.

Evaluation of MCM-2 Expression in TMA Cervical Specimens

Background Minichromosome maintenance proteins (MCM) are highly expressed in actively replicating cells. The need for biological markers for cervical carcinoma and its precursor lesions is emerging. Our main aim was to determine the immunohistochemical expression of MCM-2 in HIV-positive and -negative dysplastic cervical specimens. Methods Immunohistochemical analysis of MCM-2 was performed in a total of 352 cervical TMA specimens of normal control, low-grade CIN, high-grade CIN and invasive tumor. 38 specimens were from HIV-positive women. A receiver operating characteristic (ROC) curve was constructed to determine the best cutoff to diagnose high-grade CIN and invasive cervical cancer. Results In the progression from normal epithelium to high-grade CIN and invasive tumor we found significant differences in the MCM-2 expression (p<0.05). Based on the ROC curve of 80% with an area under the curve (AUC) of 0.78, expression of MCM-2 to diagnose high-grade CIN and invasive tumor resulted in sensitivity of 81%, specificity of 66%, a positive predictive value (PPV) of 86% and a negative predictive value (NPV) of 57%. HIV-positive cervices revealed a decreasing expression of MCM-2 in both LGCIN and HGCIN compared with HIV-negative specimens (p<0.0001). Conclusions The present study suggests that immunohistochemical MCM-2 may not be a promising biomarker for diagnosing high-grade CIN and invasive cancer.

Immunoblastic morphology in diffuse large B-cell lymphoma is associated with a nongerminal center immunophenotypic profile

Diffuse large B cell lymphomas (DLCBL) are a group of lymphomas whose biologic and prognostic diversity has been recently well characterized. There is also morphologic heterogeneity, but the relevance of subclassification remains uncertain. The World Health Organization Classification states that pathologists have the choice to use only the term diffuse large B-cell lymphoma or to use one of the specific morphologic variants. The aim of the present study was to evaluate if there is an association between immunoblastic morphology and the immunophenotypic profile in DLBCL. Two observers reviewed 117 DLBCL cases. Cases of immunoblastic lymphoma and cases of centroblastic polymorphic lymphoma with more than 50% immunoblasts were defined as having immunoblastic morphology. Immunohistochemistry was performed on tissue microarray slides to establish the immunophenotypic profile. Patients with immunoblastic morphology more frequently had a non-GCB phenotype (94%vs 6%). This finding suggests that the morphological subclassification of DLBCL does have biological meaning, in line with recent evidence indicating that the immunoblastic morphology should not be overlooked in lymphoma classification.

Correlation of MCM2 detection with stage and virology of cervical cancer

The highly conserved mini-chromosome maintenance proteins (MCM) are important in the initiation of DNA replication. Few studies have correlated MCM expression with the progression of cancer. Objectives (i) To analyze the expression of MCM2 in cervical cancer; (ii) to correlate MCM2 expression with the clinical tumor staging according to FIGO classification, and (iii) to relate HPV type to MCM2 expression. Methods Tissue micro-arrays (TMA) from patients with invasive cervical cancer and controls were analyzed. Human papillomavirus (HPV) DNA detection and HPV types were determined by in situ hybridization, PCR, and sequencing. MCM2 expression was analyzed by immunohistochemistry. Results The most prevalent HPV types found in invasive cancer were HPV 16 (66.6%), followed by HPV 33 (11.8%), and HPV 35 (3.6%). An increased (p<0.05) expression of MCM2 was found in invasive cervical cancers compared to controls. Moreover, a strong correlation was found between the MCM2-positive cells and the presence of HPV DNA detected by in situ hybridization. No statistically significant difference was observed between MCM2 expression and FIGO stage. Conclusions The present study shows that HPV-infected cells strongly express MCM2; nevertheless, our data suggests that MCM2 is not a good biomarker when comparing the different clinical stages of cervical cancer.