A simple and economical method for the manual construction of well-aligned tissue arrays

Matrix Metalloproteinases 2 and 9 and Their Tissue Inhibitors in the Diagnostics of Medullary Thyroid Carcinoma

Medullary Thyroid Carcinoma (MTC) is a tumor of the neuroendocrine system. In recent years, the need to assess the MTC diagnostic-related parameters has emerged with the aim to elucidate the mechanisms involved in this pathology. The objective of this study was to evaluate the role of Matrix Metalloproteinases (MMPs) 2 and 9, their tissue inhibitors of matrix metalloproteinases (TIMPs), S100 protein, and amyloid in the diagnostic of MTC. Thirty-two samples with MTC (72% women) were included in this cross-sectional study and divided by groups: T category 1 (T1)≤20 mm and T category 2 (T2) 20 to 40 mm of tumor size. MMPs 2 and 9, TIMPs 2 and 1, S100 protein, and calcitonin in tissues were obtained by immunohistochemical techniques. The presence of amyloid in tissue sections was detected on Thioflavin T-stained slides under fluorescent microscope. Percentage of positive cells (P) observed for MMP-2 was higher in those samples presenting T2 MTC with respect to those with T1 MTC ( P <0.05). Moreover, P-MMP-2 showed a direct correlation with higher T category of MTC (Rho=0.439, P  < 0.001), whereas P-MPP-9 was directly correlated with S100 protein and the intensity of calcitonin in tissues (Rho=0.419, P =0.017; Rho=0.422, P =0.016, respectively. Therefore, MMPs were directly correlated with some traditional biomarkers of MTC. In this regard, P-MMP-2 was more expressed in type 2 MTC. Combining the analysis of traditional and other useful biomarkers of MTC as MMPs 2 and 9 could be a useful strategy in the diagnostic of MTC.

Relationship between Trace Elements and Matrix Metalloproteinases 2 and 9 and their Tissue Inhibitors in Medullary Thyroid Carcinoma

Medullary Thyroid Carcinoma (MTC) constitutes around 5% of all thyroid cancers. Trace elements assessment has emerged as a useful strategy in the diagnostics of MTC combined with Matrix Metalloproteinases (MMPs) and Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) analysis. The aim of this study was to compare the presence and content of trace elements (i.e., Copper (Cu), Zinc (Zn), Iron (Fe), and Manganese (Mn)) in MTC with respect to control samples and their potential relationship with markers of MTC in tissues. The study included 26 patients who had undergone thyroidectomy, due to the diagnosis of MTC and 17 patients as control. We combined tumour pathology and staging, immunohistochemical analysis of calcitonin, MMPs, and TIMPs, with analytical biochemistry using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) to determine the levels of trace elements. No differences by MTC type for MMPs and their TIPMs, although strong TIMP-1 and TIMP-2 immunohistochemical expression of MTC were unveiled. Additionally, Zn, Fe, and Mn tended to be decreased, and Cu to be increased in samples presenting MTC with respect to controls. Moreover, Zn was the unique trace element which seemed to be correlated with MMPs and TIMPs. Trace elements such as Zn, Fe, and Mn are decreased in tissues affected by MTC. In addition, Zn may be the trace element which saves more relationship with the proportion and intensity of MMPs, being considered altogether useful biomarkers of MTC. We therefore suggest the analysis of novel and traditional markers of MTC as a novel approach in this pathology.

Overview on Techniques to Construct Tissue Arrays with Special Emphasis on Tissue Microarrays

With the advent of new histopathological staining techniques (histochemistry, immunohistochemistry, in situ hybridization) and the discovery of thousands of new genes, mRNA, and proteins by molecular biology, the need grew for a technique to compare many different cells or tissues on one slide in a cost effective manner and with the possibility to easily track the identity of each specimen: the tissue array (TA). Basically, a TA consists of at least two different specimens per slide. TAs differ in the kind of specimens, the number of specimens installed, the dimension of the specimens, the arrangement of the specimens, the embedding medium, the technique to prepare the specimens to be installed, and the technique to construct the TA itself. A TA can be constructed by arranging the tissue specimens in a mold and subsequently pouring the mold with the embedding medium of choice. In contrast, preformed so-called recipient blocks consisting of the embedding medium of choice have punched, drilled, or poured holes of different diameters and distances in which the cells or tissue biopsies will be deployed manually, semi-automatically, or automatically. The costs of constructing a TA differ from a few to thousands of Euros depending on the technique/equipment used. Remarkably high quality TAs can be also achieved by low cost techniques.

In-house Manual Construction of High-Density and High-Quality Tissue Microarrays by Using Homemade Recipient Agarose-Paraffin Blocks

Background

Self-made tissue punches can be effectively used to punch holes in blank recipient paraffin blocks and extract tissue cores from the donor paraffin blocks for the low-cost construction of tissue microarrays (TMAs). However, variable degrees of section distortion and loss of the tissue cores can occurs during cutting of the TMAs, posing technical problems for in-house manual construction of high-density TMAs. We aimed to update the method for in-house manual TMA construction to improve the quality of high-density TMAs.

Methods

Blocks of agarose gel were subjected to the standard tissue processing and embedding procedure to prepare recipient agarose-paraffin blocks. The self-made tissue punches and recipient agarose-paraffin blocks were used to construct TMAs, which were completely melted and re-embedded in paraffin to make finished TMA blocks.

Results

The donor tissue cores were completely integrated into the surrounding paraffin of the recipient blocks. This method enabled us to construct high-density TMAs with significantly less section distortion or loss of tissue cores during microtomy.

Conclusions

Simple and inexpensive construction of high-density and high-quality TMAs can be warranted by using paraffinized agarose gels as recipient blocks.

Construction of high-density tissue microarrays at low cost by using self-made manual microarray kits and recipient paraffin blocks

BACKGROUND

Advances of tissue microarray (TMA) technology have enabled simultaneous in situ analysis of biomarker expression in a large number of archived pathology specimens. However, the relatively high cost of TMA construction may hamper many researchers from using this essential tool of modern pathology research. We discuss methods for making TMA kits and recipient blocks for manual construction of high-density TMAs at low cost.

METHODS

Ordinary cannula piercing needles, hypodermic needles, bone marrow biopsy needles, metallic ink cartridges of ballpoint pens, and disposable skin biopsy punches were used to construct self-made manual TMA kits. The recipient blocks were manufactured by boring holes in the conventional bare paraffin blocks. A mini electric hand drill and a microcompound table assembled on a drill stand were used to maximize the capacity of the recipient blocks.

RESULTS

By using TMA kits made from cannula piercing needles (16- and 18-gauge), it was possible to construct TMAs with 1 mm×140 cores, 0.6 mm×320 cores, 2 mm×70 cores, 3 mm×35 cores, and 5 mm×12 cores. The capacity of the recipient blocks could be dramatically increased by drilling holes.

CONCLUSIONS

Construction of TMAs using self-made TMA kits is an inexpensive alternative to construction of TMAs using commercial devices.

Tissue microarray-based evaluation of Chromatin Assembly Factor-1 (CAF-1)/p60 as tumour prognostic marker

In this study we aimed to confirm the emerging role of Chromatin Assembly Factor 1 (CAF-1 p60) as a new proliferation and prognostic marker for cancer and to test the usefulness of the tissue microarray technique (TMA) for CAF-1 p60 rapid screening in several human malignancies. CAF-1 is a histone chaperone, regulating chromatin dynamics during DNA replication and repair in eukaryotics. TMA is a powerful high-throughput methodology in the study of cancer, allowing simultaneous assessment of different biomarkers within large numbers of tissue specimens. We generated TMA taking 3 mm diameter-core biopsies from oral squamous cell carcinoma, prostate cancer, salivary gland tumours and skin melanoma specimens, which had been previously tested for CAF-1 p60 on routine tissue sections. We also analysed, for the first time, 30 larynx and 30 skin squamous cell carcinomas. CAF-1 p60 resulted over-expressed in both the tissue sections and the TMA specimens, with the highest levels of expression in tumours which were more aggressive and metastasizing. Notably, a high degree of agreement was found between the CAF-1 p60 assessment on TMAs and on routine tissue sections. Our findings confirm the prognostic role of CAF-1 p60 and indicate TMA as a really advantageous method for CAF-1 p60 immunohistochemical screening, allowing savings on both tissue quantity and operator-time.

Overexpression of chromatin assembly factor-1 p60, poly(ADP-ribose) polymerase 1 and nestin predicts metastasizing behaviour of oral cancer

Aims

The natural history of oral squamous cell carcinomas (OSCCs) is variable and difficult to predict. This study aimed to assess the value of the expression of poly(ADP-ribose) polymerase 1 (PARP-1), chromatin assembly factor-1 (CAF-1)/p60 and the stem cell markers CD133, CD166, CD44, CD44v6 and nestin as markers of outcome and progression-free survival in OSCC patients.

Methods

Clinical data were collected from 66 patients (41 male and 25 female, aged 29–92 years) who underwent surgery for OSCC of the tongue, floor, lips, and palate. During follow-up (range: 12–131 months), 14 patients experienced relapse/metastasis and/or death. The study was performed by immunohistochemistry on paraffin-embedded tumour tissues, western blot analysis of tumour protein lysates and human cell lines, and RNA silencing assays. In addition, the human papillomavirus (HPV) status of primary tumours was evaluated by immunohistochemistry and viral subtyping. Univariate and multivariate analyses were performed to determine the correlation between these parameters and the clinical and pathological variables of the study population.

Results and conclusions

We found that a PARP-1^high/CAF-1 p60^high/nestin^high phenotype characterized the OSCCs with the worst prognosis (all HPV-negative). This may be of benefit in clinical management, since radio-enhancing anti-PARP-1 and/or anti-CAF-1/p60 agents may allow radioresistance to be bypassed in the nestin-overexpressing, metastasizing OSCC cells.

Improved technique for manually constructing tissue microarrays for large-core arrays

Tissue microarrays were originally developed to enable alignment of multiple tissue cores in a single paraffin block and to enable high-throughput laboratory analysis. However, a major drawback is the loss of tissue cores during slide preparation, especially when sectioning the tissue block. Tissue cylinders directly aligned in the metal box without preheating tend to detach from the surrounding paraffin, which results in incomplete or folded tissue sections. The proposed solution is preheating all tissue cylinders on a hot plate to facilitate fusion between the paraffin within the core and the paraffin surrounding the core. In this study, 6 tissue microarray blocks were constructed from 528 tissue cores extracted from various formalin-fixed, paraffin-embedded human tissue samples. The tissue cores in the arrays revealed good homogenization with the surrounding paraffin wax, and the tissue sections were obtained intact. Both hematoxylin-eosin and immunohistochemical staining confirmed satisfactory results. This simple and economical method is easily performed in the laboratory without expensive instrumentation.

Downregulation of Krüppel-like factor 9 in human colorectal cancer

Mammalian Sp and Krüppel-like factors (KLF), a family of zinc finger-containing transcription factors, are involved in growth control, proliferation, apoptosis and angiogenesis of a wide variety of tissues and cells. Several KLF have been linked to various types of human cancers, but the relationship between Krüppel-like factor 9 (KLF9) and colorectal cancer has not been explored. The purpose of the present study was to investigate KLF9 expression in human colorectal cancer tissue. KLF9 mRNA was detected on quantitative real-time reverse transcriptase-polymerase chain reaction (Q-PCR). Of the 50 cancerous tissues examined, 86% (43/50) expressed lower levels of KLF9 mRNA than individually matched normal mucosa (P < 0.0001). On western blot, reduced or absent expression of KLF9 protein was observed in 65% (13/20) of the samples (P < 0.01). A total of 81% (35/43) of normal samples had expression of KLF9 protein, whereas its protein was detected in only 9% (4/43) of tumor tissues (P < 0.001) on tissue microarray. These results indicate that KLF9 may be involved in the carcinogenesis of human colorectal cancer.

Use of Caveolin-1, Thyroid Transcription Factor-1, and Cytokeratins 7 and 20 in Discriminating Between Primary and Secondary Pulmonary Adenocarcinoma from Breast or Colonic Origin

The objectives of this study were firstly to compare the immunostaining patterns of antibodies against caveolin-1, thyroid transcription factor-1 (TTF-1), cytokeratin 7 (CK7) and cytokeratin 20 (CK20) in primary and secondary pulmonary adenocarcinomas of breast or colonic origin, and secondly, to investigate their use alone and in combination, in distinguishing between primary and secondary lung adenocarcinomas from breast or colonic origin. Of the 49 lung adenocarcinoma specimens that were enrolled in this study, 30 were primary pulmonary adenocarcinomas, and 19 (9, breast origin; 10, colonic origin) were metastatic pulmonary carcinomas. Immunohistochemical staining was used to detect the expression of caveolin-1, TTF-1, CK7, and CK20. Primary pulmonary adenocarcinoma most often had the CK7-positive/CK20-negative immunohistochemical phenotype and was either TTF-1 positive or caveolin-1 negative. Secondary pulmonary adenocarcinoma of breast origin most often had the CK7-positive/CK20-negative immunohistochemical phenotype and was either TTF-1 negative or caveolin-1 positive, while secondary pulmonary adenocarcinoma of colonic origin most often had the CK20-positive/CK7-negative immunohistochemical phenotype and was either TTF-1 negative or caveolin-1 positive. The results suggest that caveolin-1, TTF-1, or CK7/CK20 alone did not distinguish reliably between primary and secondary pulmonary adenocarcinomas originating from breast or colon. The use of a panel of antibodies that includes TTF-1, caveolin-1, and CK7/CK20 may have higher sensitivity in discriminating between primary adenocarcinomas and metastatic lung adenocarcinomas from breast or colonic origin.