Expression of Toll-like receptor 4 and beta 1 integrin in breast cancer

Clinicopathological Significance and Prognostic Role of High Mobility Group Box 1 (HMGB1), Toll-Like Receptor (TLR) 2 and TLR4 in Breast Cancer

High-mobility group box 1 (HMGB1) functions as damage-associated molecular pattern (DAMPs), released into extracellular space during cellular stress. Extracellular HMGB1 act as signal molecules through Toll-like receptor (TLR) 2 or TLR4, exerting diverse functions in both normal cells and malignant cells including breast cancer. However, their comprehensive examination in breast cancer tissues is lacking. Thus, we immunolocalized them in 112 breast cancer tissues, correlating their immunoreactivity with clinicopathological parameters and clinical outcomes to clarify their significance in breast cancer. We demonstrated that nuclear HMGB1 immunoreactivity was correlated with tumor progression and longer disease-free survival. In contrast, TLR2 immunoreactivity was correlated with increased cell proliferation and shorter disease-free survival, dependent on cytoplasmic HMGB1 immunoreactivity. Additionally, TLR4 immunoreactivity correlated with chemoresistance, regardless of cytoplasmic HMGB1 immunoreactivity. It was therefore considered that TLR2 collaboratively contributed to breast cancer progression with HMGB1-DAMPs to become a worse prognostic factor. Meanwhile, TLR4 served as a worse prognostic factor associated with chemoresistance, irrespective of HMGB1.

Prognostic and clinicopathological significance of TLR4 expression in patients with breast cancer: a meta-analysis

Background

The prognostic value of Toll-like receptor 4 (TLR4) in breast cancer remains to be determined. Therefore, this paper aims to conduct a meta-analysis to assess the correlation between TLR4 and clinicopathological indicators as well as survival outcomes in breast cancer.

Method

Related literature retrieved from Embase, PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI) and China Wanfang. The search deadline is April 12, 2023. The outcome measures employed in the study comprised hazard ratio (HR), odds ratio (OR), and 95% confidence interval (CI) as effective indices. The data analysis was conducted using Stata 17.0 software.

Results

High TLR4 expression was associated with lymph node metastasis (OR=2.077, 95%CI=1.160-3.717, P= 0.014), tumor size (≥2 cm) (OR=2.194, 95%CI= 1.398-3.445, P= 0.001), PR expression (OR = 0.700, 95% CI = 0.505-0.971, P= 0.033), and clinical stage (OR = 3.578, 95%CI= 3.578-5.817, P<0.05), but not with histological grade (95%CI= 0.976-1.735, P= 0.072), ER expression (OR = 1.125, 95% CI = 0.492-2.571,P= 0.781), and HER-2 status (OR = 1.241, 95% CI = 0.733-2.101, P = 0.422). In addition, TLR4 overexpression was an independent prognostic indicator of DFS (HR= 1.480, 95%CI= 1.028- 2.130, p= 0.035) in breast cancer patients, but not related to OS(HR=1.730, 95%CI= 0.979-3.057, P= 0.059).

Conclusions

From our main analysis results, high TLR4 expression is associated with lymph node metastasis, larger tumor size (≥2 cm), later clinical stage, negative PR expression and shorter DFS, suggesting poor prognosis in breast cancer patients.

Integrin β5 is an independent prognostic marker for intrahepatic cholangiocarcinoma in a Chinese population

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver tumor and a major cause of cancer mortality worldwide. Integrin β5 (ITGB5) is considered to be involved in the intercellular signal transduction and regulation of tumorigenesis and development. The present study investigated the association between ITGB5 expression levels and the prognosis of ICC, as well as the effects of ITGB5 on the proliferation and invasion of ICC cells. RNA-sequencing transcriptomic profiling data of ICC samples were retrieved from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Tissue specimens from patients with ICC treated at Taizhou People's Hospital were collected and the ITGB5 expression levels were evaluated using immunohistochemical staining. The biological function of ITGB5 in ICC was investigated using Gene Ontology (GO), Gene Set Enrichment Analysis (GSEA) and in vitro experiments using HuCCT1 cells. After knocking down ITGB5 expression, cell proliferation was detected using Cell Counting Kit-8 assay, while cell invasion was assessed using Transwell assays. According to TCGA dataset, ITGB5 was highly expressed in ICC; however, there was no significant difference in prognosis between patients with high and low ITGB5 expression levels. High expression of ITGB5 was present in the tissues of patients with ICC from the GEO database, which was associated with poor prognosis. Survival analyses of the clinical data obtained in the present study revealed that high expression levels of ITGB5 in patients with ICC were associated with a reduced overall survival. GO and GSEA indicated that genes associated with ITGB5 were enriched in the extracellular matrix-receptor interaction and focal adhesion signaling pathways. Silencing ITGB5 inhibited the proliferation and invasion of ICC cells. In conclusion, ITGB5 may act as an essential regulator of ICC development and progression by influencing the proliferation and invasion of ICC cells. However, future studies with larger sample sizes are required to validate the role of ITGB5 in the prognosis of patients with ICC.

Inhibition of ITGB1 enhance the anti-tumor effect of cetuximab in colorectal cancer cell

BACKGROUND

Colorectal cancer is the second commonly seen cancer around the world and accounts for 13% of all human cancers. Among them, 25% of all case were diagnosed with metastasis and 50% occurs metastasis during the development of disease. Cetuximab is a chimeric monoclonal antibody against epidermal growth factor receptor, and is used for treatment of metastatic colorectal cancer alone or combined with chemotherapy or radiation therapy. Integrin-beta 1 (ITGB1), which is also known as CD29, and plays an important role in development of malignant cancers. However, the effect of ITGB1 in promoting the anti-tumor effect of cetuximab is not fully understand.

METHODS

The model of ITGB1 inhibition and overexpression was firstly constructed in LS174T cells, and the viability of cells in each group was detected using CCK-8 assay. The expression of key factors in tumor formation process at transcription level was detected using real-time quantitative polymerase chain reaction method. The expression of key proteins in metastasis process, cell apoptosis and activation of Ras/Raf/MEK signaling pathway was detected using western blotting analysis. And the concentration of key factors of in tumor formation process in cultured medium of LS174T cells were detected using enzyme-linked immunosorbent assay method.

RESULTS

We found that cetuximab could inhibit the proliferation of LS174T cells, and inhibition of ITGB1 enhanced this effect while overexpression of ITGB1 reduced this effect. We further found that cetuximab could inhibit the expression and secretion of extracellular matrix degradation related molecules in cultured medium and transcription level. Besides, we also found that the expression of key factors in angiogenesis and extracellular matrix degradation related proteins were also reduced after cetuximab treatment. These effects might be mediated by Ras/Raf/MAPK signaling pathway and enhanced after inhibition of ITGB1 expression.

CONCLUSION

Inhibition of ITGB1 might be a new therapeutic method in colorectal cancer.

Breast Cancer Tumor Stroma: Cellular Components, Phenotypic Heterogeneity, Intercellular Communication, Prognostic Implications and Therapeutic Opportunities

Although the mechanisms underlying the genesis and progression of breast cancer are better understood than ever, it is still the most frequent malignant tumor in women and one of the leading causes of cancer death. Therefore, we need to establish new approaches that lead us to better understand the prognosis of this heterogeneous systemic disease and to propose new therapeutic strategies. Cancer is not only a malignant transformation of the epithelial cells merely based on their autonomous or acquired proliferative capacity. Today, data support the concept of cancer as an ecosystem based on a cellular sociology, with diverse components and complex interactions between them. Among the different cell types that make up the stroma, which have a relevant role in the dynamics of tumor/stromal cell interactions, the main ones are cancer associated fibroblasts, endothelial cells, immune cells and mesenchymal stromal cells. Several factors expressed by the stroma of breast carcinomas are associated with the development of metastasis, such as matrix metalloproteases, their tissular inhibitors or some of their regulators like integrins, cytokines or toll-like receptors. Based on the expression of these factors, two types of breast cancer stroma can be proposed with significantly different influence on the prognosis of patients. In addition, there is evidence about the existence of bi-directional signals between cancer cells and tumor stroma cells with prognostic implications, suggesting new therapeutic strategies in breast cancer.

Toll-like receptor 4 and breast cancer: an updated systematic review

Toll-like receptors (TLRs) may play dual roles in human cancers. TLR4 is a key molecule which may participate in both friend and foe roles against breast cancer. This review article collected recent data regarding the mechanisms used by TLR4 in the eradication of breast cancer cells and induction of the tumor cells, and discussed the mechanisms involved in the various functions of TLR4. The literature searches revealed that TLR4 is a key molecule that participates in breast cancer cell eradication or induction of breast cancer development and also transformation of the normal cells. TLR4 eradicates breast cancer cells via recognition of their DAMPs and then induces immune responses. Over-expression of TLR4 and also alterations in its signaling, including association of some intrinsic pathways such as TGF-β signaling and TP53, are the crucial factors to alter TLR4 functions against breast cancer.

Prognostic role of Toll-like receptors in cancer: a meta-analysis

Background

Recent studies have shown that Toll-like receptors (TLRs) may be associated with cancers. The aim of this meta-analysis is to summarize the predicting role of TLRs for survival in patients with a variety of carcinomas.

Materials and methods

Eligible studies were identified and assessed for quality through multiple search strategies. We collected data from studies investigating the relationship between the expression level of TLRs and survival in cancer patients. Studies were pooled and combined hazard ratios (HRs) of TLRs for survival were analyzed.

Results

A total of 24 studies, including 2,812 patients with various cancers, were identified for the meta-analysis. Importantly, this meta-analysis showed that higher expression levels of TLR4 or TLR7 in tumor tissues could predict poorer survival, with the pooled HR being 1.29 (95% CI: 1.17, 1.42) and 1.71 (95% CI: 1.38, 2.12), respectively. However, higher expression of TLR9 had no significant association with outcome as HR was 0.84 (95% CI: 0.62, 1.115). Heterogeneity existed in TLR4 and TLR9 studies (P-value <0.001) but not in TLR7 studies (P-value >0.05).

Conclusion

The expression level of TLR4 or TLR7 in cancerous tissue may have a prognosis value in patients with various cancers.

Prognostic value of increased integrin-beta 1 expression in solid cancers: a meta-analysis

Integrin-beta 1 (ITGB1) is aberrantly overexpressed or downregulated in solid cancers; however, its prognostic value remains controversial. Therefore, we conducted a meta-analysis to explore whether ITGB1 expression is correlated with overall survival (OS) and the clinicopathological characteristics of patients with solid cancers. We systematically searched the PubMed, Embase, and Web of Science databases for eligible studies published up to June 1, 2017. In total, 22 studies involving 3,666 patients were included. A sensitivity analysis was performed to assess the validity and reliability of the pooled OS. Among the 22 studies, 7 focused on lung cancer, 3 focused on colorectal cancer, 6 focused on breast cancer, 3 involved melanoma, and 3 involved pancreatic cancer. The pooled results showed that high ITGB1 expression was significantly associated with worse OS in lung cancer (pooled hazard ratio [HR]=1.78, 95% CI: 1.19–2.65, p<0.05) and breast cancer (pooled HR=1.88, 95% CI: 1.46–2.42, p<0.01). In addition, a significant association was observed between high ITGB1 expression and disease-free survival in breast cancer (pooled HR=1.63, 95% CI: 1.17–2.25, p<0.001) and pancreatic cancer (pooled HR=2.49, 95% CI: 1.35–4.61, p<0.001). However, high ITGB1 expression was not related to OS in colorectal cancer, pancreatic cancer, or melanoma. The pooled HRs used to evaluate the prognostic value of increased ITGB1 expression in lung cancer, breast cancer, and pancreatic cancer were not significantly altered, which indicates that the pooled results were robust. The results of this study indicate that the prognostic value of decreased ITGB1 expression varies among solid cancers.

Overexpression of β1 integrin contributes to polarity reversal and a poor prognosis of breast invasive micropapillary carcinoma

Invasive micropapillary carcinoma (IMPC) of the breast is a highly aggressive breast cancer. Polarity reversal exemplified by cluster growth is hypothesized to contribute to the invasiveness and metastasis of IMPC. In this study, we demonstrate that levels of β1 integrin and Rac1 expression were greater in breast IMPC than in invasive breast carcinoma of no specific type and paraneoplastic benign breast tissue. We show that silencing β1 integrin expression using the β1 integrin inhibitor AIIB2 partially restored polarity in IMPC primary cell clusters and downregulated Rac1. Thus, overexpression of β1 integrin upregulates Rac1. Univariate analysis showed that overexpression of β1 integrin and Rac1 was associated with breast cancer cell polarity reversal, lymph node metastasis, and poor disease-free survival in IMPC patients. Multivariate analysis revealed that polarity reversal was an independent predictor of poor disease-free survival. These findings indicate that overexpression of β1 integrin and the resultant upregulation of Rac1 contribute to polarity reversal and metastasis of breast IMPC, and that β1 integrin and Rac1 could be potential prognostic biomarkers and targets for treatment of breast IMPC.

The expression of Foxp3 and TLR4 in cervical cancer: association with immune escape and clinical pathology

PURPOSE

To explore the expression of forkhead/winged helix transcription factor p3(Foxp3) and toll-like receptor 4(TLR4) in cervical cancer and evaluate their clinical significance.

METHODS

Foxp3 and TLR4 protein expression was detected in 105 cervical tissue specimens including cervical cancer, cervical intraepithelial neoplasia (CIN), and healthy control samples using immunohistochemistry. Their relationship with clinicopathologic parameters was also determined.

RESULTS

Foxp3 and TLR4 had high levels of expression in cervical cancer cells (91.43 and 82.86%, respectively). Foxp3 levels were significantly associated with FIGO stage (P < 0.001) and tumor size (P = 0.034), while TLR4 levels were associated with clinical FIGO stage (P = 0.033) and lymph node metastasis (P = 0.031). Their expression levels were not correlated with age, histologic type, or differentiation (all P > 0.05). These findings suggest that Foxp3 and TLR4 may be useful prognostic indicators of cervical carcinoma. In addition, there were significant positive relationships between Foxp3 and TLR4 expression (r = 0.703, P < 0.001), which shows a possible link and synergistic role of Foxp3 and TLR4 in promoting the immune escape of cervical cancer.

CONCLUSIONS

Foxp3 and TLR4 may be useful biomarkers for patient prognosis and cervical cancer prediction and treatment.

Toll-like receptor 4 prompts human breast cancer cells invasiveness via lipopolysaccharide stimulation and is overexpressed in patients with lymph node metastasis

Toll-like receptor (TLR)4-mediated signaling has been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. This study investigated the expression and biological role of TLR4 in human breast cancer metastasis. MCF-7 and MDA-MB-231 are human breast cancer cell lines with low and high metastatic potential, respectively. Using lipopolysaccharide (LPS) to stimulate MCF-7 and MDA-MB-231 cells, expression of TLR4 mRNA and protein increased compared with that in control cells. TLR4 activation notably up-regulated expression of matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor(VEGF) mRNA and their secretion in the supernatants of both cell lines. LPS enhanced invasion of MDA-MB-231 cells by transwell assay and MCF-7 cells by wound healing assay. LPS triggered increased expression of TLR4 downstream signaling pathway protein myeloid differentiation factor 88(MyD88) and resulted in interleukin (IL)-6 and IL-10 higher production by human breast cancer cells. Stimulation of TLR4 with LPS promoted tumorigenesis and formed metastatic lesions in liver of nude mice. Moreover, expression of TLR4 and MyD88 as well as invasiveness and migration of the cells could be blocked by TLR4 antagonist. Combined with clinicopathological parameters, TLR4 was overexpressed in human breast cancer tissue and correlated with lymph node metastasis. These findings indicated that TLR4 may participate in the progression and metastasis of human breast cancer and provide a new therapeutic target.

Differential subcellular and extracellular localisations of proteins required for insulin-like growth factor- and extracellular matrix-induced signalling events in breast cancer progression

Background

Cancer metastasis is the main contributor to breast cancer fatalities as women with the metastatic disease have poorer survival outcomes than women with localised breast cancers. There is an urgent need to develop appropriate prognostic methods to stratify patients based on the propensities of their cancers to metastasise. The insulin-like growth factor (IGF)-I: IGF binding protein (IGFBP):vitronectin complexes have been shown to stimulate changes in gene expression favouring increased breast cancer cell survival and a migratory phenotype. We therefore investigated the prognostic potential of these IGF- and extracellular matrix (ECM) interaction-induced proteins in the early identification of breast cancers with a propensity to metastasise using patient-derived tissue microarrays.

Methods

Semiquantitative immunohistochemistry analyses were performed to compare the extracellular and subcellular distribution of IGF- and ECM-induced signalling proteins among matched normal, primary cancer and metastatic cancer formalin-fixed paraffin-embedded breast tissue samples.

Results

The IGF- and ECM-induced signalling proteins were differentially expressed between subcellular and extracellular localisations. Vitronectin and IGFBP-5 immunoreactivity was lower while β₁ integrin immunoreactivity was higher in the stroma surrounding metastatic cancer tissues, as compared to normal breast and primary cancer stromal tissues. Similarly, immunoreactive stratifin was found to be increased in the stroma of primary as well as metastatic breast tissues. Immunoreactive fibronectin and β₁ integrin was found to be highly expressed at the leading edge of tumours. Based on the immunoreactivity it was apparent that the cell signalling proteins AKT1 and ERK1/2 shuffled from the nucleus to the cytoplasm with tumour progression.

Conclusion

This is the first in-depth, compartmentalised analysis of the distribution of IGF- and ECM-induced signalling proteins in metastatic breast cancers. This study has provided insights into the changing pattern of cellular localisation and expression of IGF- and ECM-induced signalling proteins in different stages of breast cancer. The differential distribution of these biomarkers could provide important prognostic and predictive indicators that may assist the clinical management of breast disease, namely in the early identification of cancers with a propensity to metastasise, and/or recur following adjuvant therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-627) contains supplementary material, which is available to authorized users.

Differential expression patterns of N-acetylglucosaminyl transferases and polylactosamines in uterine lesions

Polylactosamine (polyLacNAc) is a fundamental structure in glycoconjugates and it is expressed in specific cells/tissues associated with the development and carcinogenesis. β1,3-N-acetylglucosaminyl transferases ((β3GnTs) play an important role in polyLacNAc synthesis, however the roles of these glycosyltransferases and their products in cancer progression are still unclear. In this sense, this work aimed to evaluate differential expression pattern of the N-acetylglucosaminyl transferases and polylactosamines in invasive and premalignant lesions of the uterus cervix. The expression of β3GnT2 and β3GnT3 were evaluated in normal (n=10) and uterine cervix lesions (n=120), both malignant [squamous carcinoma (SC)] and premalignant [cervical intraepithelial neoplasia (CIN), grades 1, 2 and 3] using immunohistochemistry. Besides, lectin histochemistry with Phytolacca americana lectin (PWM) and Wheat germ agglutinin (WGA) was also carried out to observe the presence of polyLacNAc chains and N-acetylglucosamine (GlcNAc), respectively. The β3GnT3 was expressed in almost all samples (99%) and β3GnT2 was higher expressed in disease samples mainly in CIN 3, when compared with normal (P=0.002), CIN 1 (P=0.009) and CIN 2 (P=0.03). The expression of polyLacNAc was higher is SC samples, when compared with normal (P=0.03), CIN 1 (P=0.02) and CIN 3 (P=0.004), and was observed only nuclear expression in nearly 50% of the SC samples, showing a statistically significant when compared with normal (P=0.01), CIN 1 (P=0.002), CIN 2 (P=0.007) and CIN 3 (P=0.04). Deferring from transferases and polyLacNAc chains, GlcNAc (WGA ligand) reveals a gradual staining pattern decrease with the increase of the lesion degree, being more expressed in CIN 1 lesions when compared with normal (P<0.0001), CIN 2 (P<0.0001), SC (P<0.0001) and CIN 3 (P=0.0003). Our data reveal that β3GnT2 and polyLacNAc may be involved in the progression of the pre-malignant lesions of the human uterine cervix. In addition, polyLacNAc expression only in the nucleus can be associated a poor prognostic in uterine lesions.

A TLR4-interacting peptide inhibits lipopolysaccharide-stimulated inflammatory responses, migration and invasion of colon cancer SW480 cells

Inflammation is a major risk factor for carcinogenesis in patients affected by chronic colitis, yet the molecular mechanisms underlying the progression from chronic inflammation to cancer are not completely understood. Activation of the Toll-like receptor 4 (TLR4)-NFκB signaling axis is associated with inflammation. Thus, we hypothesized that inhibition of TLR4-NFκB signaling might help in limiting inflammatory responses and inflammation-induced oncogenesis. In this work, we studied the effects of a TLR4-interacting surfactant protein A-derived (SPA4) peptide on lipopolysaccharide (LPS)-induced TLR4-NFκB signaling and cancer progression. We first characterized this peptide for its ability to bind the TLR4 ligand-LPS and for physico-chemical characteristics. Inflammation was induced by challenging the colon cancer SW480 cells with Escherichia coli LPS. Cells were then treated with varying amounts of the SPA4 peptide. Changes in the expression of TLR4, interleukin (IL)-1β and IL-6, in intracellular NFκB-related signal transducers (IKBα, p65, phosphorylated IKBα, phosphorylated p65, RelB, COX-2) as well as in the transcriptional activity of NFκB were studied by immunocytochemistry, immunoblotting and NFκB reporter assay, respectively. Simultaneously, the effects on LPS-induced cell migration and invasion were determined. We found that the SPA4 peptide does not bind to LPS. Rather, its binding to TLR4 inhibits the LPS-induced phosphorylation of p65, production of IL-1β and IL-6, activity of NFκB, migration and invasion of SW480 cells. In conclusion, our results suggest that the inhibition of TLR4-NFκB signaling by a TLR4-binding peptide may help for the treatment of chronic inflammation and prevention of inflammation-induced cancer in patients with colitis.

Beta 1 integrin predicts survival in breast cancer: a clinicopathological and immunohistochemical study

Background

The main focus of several studies concerned with cancer progression and metastasis is to analyze the mechanisms that allow cancer cells to interact and quickly adapt with their environment. Integrins, a family of transmembrane glycoproteins, play a major role in invasive and metastatic processes. Integrins are involved in cell adhesion in both cell-extracellular matrix and cell-cell interactions, and particularly, β1 integrin is involved in proliferation and differentiation of cells in the development of epithelial tissues. This work aimed to investigate the putative role of β1 integrin expression on survival and metastasis in patients with breast invasive ductal carcinoma (IDC). In addition, we compared the expression of β1 integrin in patients with ductal carcinoma in situ (DCIS).

Methods

Through tissue microarray (TMA) slides containing 225 samples of IDC and 67 samples of DCIS, β1 integrin expression was related with several immunohistochemical markers and clinicopathologic features of prognostic significance.

Results

β1 integrin was overexpressed in 32.8% of IDC. In IDC, β1 integrin was related with HER-2 (p = 0.019) and VEGF (p = 0.011) expression and it had a significant relationship with metastasis and death (p = 0.001 and p = 0.05, respectively). Kaplan-Meier survival analysis showed that the overexpression of this protein is very significant (p = 0.002) in specific survival (number of months between diagnosis and death caused by the disease). There were no correlation between IDC and DCIS (p = 0.559) regarding β1 integrin expression.

Conclusions

Considering that the expression of β1 integrin in breast cancer remains controversial, specially its relation with survival of patients, our findings provide further evidence that β1 integrin can be a marker of poor prognosis in breast cancer.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6652215267393871

Inherited variation in pattern recognition receptors and cancer: dangerous liaisons?

The group of pattern recognition receptors includes families of Toll-like receptors, NOD-like receptors, C-type lectin receptors, and RIG-I-like receptors. They are key sensors for a number of infectious agents, some of which are carcinogenic, and they launch an immune response against them. Inherited structural variation in genes encoding these receptors and proteins of their signaling pathways may affect their function, modulating cancer risk and features of cancer progression. Relevant malignancies, valuable gene polymorphisms, prime questions about future directions, and answers to these questions are analyzed in this review. It is possible to suggest that polymorphisms of genes encoding pattern recognition receptors and proteins of their signaling pathways may be associated with almost all cancer types, particularly with those in which carcinogenic infectious agents are responsible for the substantial share of cases (namely gastric cancer, colorectal cancer, liver cancer, cervical cancer, and nasopharyngeal carcinoma). The concept of selection of polymorphisms for further oncogenomic investigation, based on a combination of results from basic and epidemiological studies, is proposed.