A practical guide to constructing and using tissue microarrays

Association between expression of inflammatory markers in normal breast tissue and mammographic density among premenopausal and postmenopausal women

OBJECTIVE

Inflammatory markers may be associated with breast cancer risk. We assessed the association between expression levels of proinflammatory (interleukin 6, tumor necrosis factor-α, C-reactive protein, cyclooxygenase 2, leptin, serum amyloid A1, interleukin 8, and signal transducer and activator of transcription 3) and anti-inflammatory markers (transforming growth factor-β, interleukin 10, and lactoferrin) in normal breast tissue with mammographic density, a strong breast cancer risk indicator, among 163 breast cancer patients.

METHODS

The expression of inflammatory markers was visually evaluated on immunohistochemistry stained slides. The percent mammographic density (PMD) was estimated by a computer-assisted method in the contralateral cancer-free breast. We used generalized linear models to estimate means of PMD by median expression levels of the inflammatory markers while adjusting for age and waist circumference.

RESULTS

Higher expression levels (above median) of the proinflammatory marker interleukin 6 were associated with higher PMD among all women (24.1% vs 18.5%, P = 0.007). Similarly, higher expression levels (above median) of the proinflammatory markers (interleukin 6, tumor necrosis factor-α, C-reactive protein, and interleukin 8) were associated with higher PMD among premenopausal women (absolute difference in the PMD of 8.8% [P = 0.006], 7.7% [P = 0.022], 6.7% [P = 0.037], and 16.5% [P = 0.032], respectively). Higher expression levels (above median) of the anti-inflammatory marker transforming growth factor-β were associated with lower PMD among all (18.8% vs 24.3%, P = 0.005) and postmenopausal women (14.5% vs 20.7%, P = 0.013).

CONCLUSIONS

Our results provide support for the hypothesized role of inflammatory markers in breast carcinogenesis through their effects on mammographic density. Inflammatory markers could be targeted in future breast cancer prevention interventions.

Protocols for Tissue Microarrays in Prostate Cancer Studies

Tissue microarray (TMA) technology is a method for high-throughput analysis of tissue biomarkers, commonly used in translational cancer research. TMAs allow performing a variety of in situ applications on hundreds of tissue samples simultaneously using the same protocols as for conventional slides. Thereby, precious material from patient samples remains largely preserved while costs in resources and time in laboratory processing decrease. Therefore, a TMA is a powerful tool to identify and study biomarkers that may have a potential diagnostic, prognostic, and predictive value. Depending on the research question, there are different types of TMAs, such as progression TMA, outcome TMA, and tumor heterogeneity TMA. Since the first introduction of the TMA method almost 20 years ago, most laboratories used manual tissue arrayers for manufacturing. Nowadays, automatic or semiautomatic devices are commercially available, which largely facilitates the technical construction. However, preparatory work remains the most time-consuming part in preparing TMAs. This chapter focuses on issues involved in design and construction of prostate cancer TMAs.

High intratumoural but not peritumoural inflammatory host response is associated with better prognosis in primary resected oesophageal adenocarcinomas

The host inflammatory response plays an important role in many solid malignancies. Studies on oesophageal adenocarcinomas (EACs) point towards a beneficial role of pronounced immunoreaction, however, congruent results have yet to be obtained. We analysed 111 primary resected EAC using a tissue microarray containing three cores of the tumour centre and the periphery per case. Overall inflammation was assessed by histomorphology. Tumour infiltrating lymphocytes (TILs) were characterised by immunohistochemistry for CD3, CD8 and FoxP3, and evaluated by image analysis (Aperio ImageScope). High levels of inflammation in the tumour centre, but not the periphery were associated with better patient survival (p = 0.001), similar to high counts of intratumoural FoxP3+, CD3+, CD8+ TILs (p = 0.001; p = 0.027; p = 0.038) and a combination of CD3+/CD8+/FoxP3+ TILs, the latter displaying three different prognostic groups (triple high/mixed/triple low; p=0.003). Intratumoural inflammation [hazard ratio (HR) = 0.432; p = 0.030], FoxP3+ TIL counts (HR = 0.411; p = 0.033) and the combination CD3+/CD8+/FoxP3+ TILs (HR = 0.173; p = 0.006) were also independent prognostic parameters. In summary, both high grade total inflammation and high TIL counts in the tumour centre, but not the tumour periphery, show a beneficial prognostic impact on EAC. This may be a target for novel therapeutic options but also serves as prognostic indicator in these tumours.

Tumour infiltrating lymphocytes correlate with improved survival in patients with oesophageal adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma (OAC) is increasingly common in the west, and survival remains poor at 10-15 % at 5 years. Immune responses are increasingly implicated as a determining factor of tumour progression. The ability of lymphocytes to recognise tumour antigens provides a mechanism for a host immune attack against cancer providing a potential treatment strategy.

MATERIALS AND METHODS

Tumour infiltrating lymphocytes (TILs: CD3+, CD4+, CD8+ and FOXp3+) were assessed by immunohistochemistry using tissue microarrays in a contemporary and homogeneous cohort of OAC patients (n = 128) undergoing curative treatment.

RESULTS

Multivariate analysis identified three independent prognostic factors for improved cancer-specific survival (CSS): increased CD8+ TILs (p = 0.003), completeness of resection (p < 0.0001) and lower pathological N stage (p < 0.0001). Independent prognostic factors for favourable disease-free survival included surgery-only treatment (p = 0.015), completeness of resection (p = 0.001), increased CD8+ TILs (p < 0.0001) and reduced pathological N stage (p < 0.0001). Higher levels of TILs in the pathological specimen were associated with significant pathological response to neoadjuvant chemotherapy (NAC). On multivariate analysis increased levels of CD4+ (p = 0.017) and CD8+ TILs (p = 0.005) were associated with significant local tumour regression and lymph node downstaging, respectively.

DISCUSSION

Our results establish an association of TILs and survival in OAC, as seen in other solid tumours, and identify particular TIL subsets that are present at higher levels in patients who responded to NAC compared to non-responders. These findings highlight potential therapeutic strategies in EAC based on utilising the host immunological response and highlight the immune responses biomarker potential.

Breast Cancer Detection by B7-H3-Targeted Ultrasound Molecular Imaging

Ultrasound complements mammography as an imaging modality for breast cancer detection, especially in patients with dense breast tissue, but its utility is limited by low diagnostic accuracy. One emerging molecular tool to address this limitation involves contrast-enhanced ultrasound using microbubbles targeted to molecular signatures on tumor neovasculature. In this study, we illustrate how tumor vascular expression of B7-H3 (CD276), a member of the B7 family of ligands for T-cell coregulatory receptors, can be incorporated into an ultrasound method that can distinguish normal, benign, precursor, and malignant breast pathologies for diagnostic purposes. Through an IHC analysis of 248 human breast specimens, we found that vascular expression of B7-H3 was selectively and significantly higher in breast cancer tissues. B7-H3 immunostaining on blood vessels distinguished benign/precursors from malignant lesions with high diagnostic accuracy in human specimens. In a transgenic mouse model of cancer, the B7-H3-targeted ultrasound imaging signal was increased significantly in breast cancer tissues and highly correlated with ex vivo expression levels of B7-H3 on quantitative immunofluorescence. Our findings offer a preclinical proof of concept for the use of B7-H3-targeted ultrasound molecular imaging as a tool to improve the diagnostic accuracy of breast cancer detection in patients.

Tissue microarrays: construction and use

Tissue microarrays (TMAs) enable high-throughput tissue analysis by selecting a large number of -paraffin-embedded donor tissue block cores and transferring these tissue cores into a positionally encoded array in the recipient TMA block. Once TMAs are constructed, a variety of analysis may be performed on the arrays including histochemical, immunohistochemical, or immunofluorescent staining, and in situ hybridization for DNA or RNA. TMAs offer a cost-effective method for performing parallel analysis of a large number of tissue samples. In this chapter we outline the method of TMA construction with an emphasis on providing useful information in the analysis of a variety of pancreatic neoplasms, including pancreatic adenocarcinomas and pre-invasive lesions. The technique of TMA construction in this chapter is restricted to the use of formalin-fixed paraffin-embedded tissue.