The expression and prognostic value of protein tyrosine kinase 6 in early-stage cervical squamous cell cancer.

BACKGROUND: Protein tyrosine kinase 6 (PTK6) is overexpressed in many epithelial tumors and predicts poor prognosis. However, PTK6 expression status and its role in cervical squamous cell cancer are unknown. This study aimed to investigate the expression level and clinical significance of PTK6 in early-stage cervical squamous cell cancer. METHODS: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting analysis were performed to detect PTK6 mRNA and protein expression levels in 10 freshly frozen, early-stage cervical squamous cell cancer specimens and adjacent non-tumorous cervical tissues. The expression of PTK6 was detected using immunohistochemical staining in 150 formalin-fixed, paraffin-embedded, early-stage cervical squamous cell cancer sections and 10 normal cervical tissue sections. RESULTS: The mRNA and protein levels of PTK6 in cancer tissues were higher than those in adjacent non-tumorous cervical tissues. Immunohistochemical analysis showed that PTK6 was not expressed in normal cervical tissues but was overexpressed in the cytoplasm of cervical squamous cell cancer cells. The level of PTK6 expression was significantly associated with tumor grade (P = 0.020). The 5-year overall survival rate of patients with high PTK6 expression was lower than that of patients with low PTK6 expression (81.3% vs. 96.2%, P = 0.008). Multivariate Cox regression analysis showed that the expression level of PTK6 in cervical squamous cell cancer was an independent prognostic factor for patient survival (hazard ratio = 5.999, 95% confidence interval 1.622-22.191, P < 0.05). CONCLUSIONS: PTK6 is overexpressed in cervical squamous cell cancer. Increased PTK6 expression is associated with reduced 5-year overall survival. PTK6 expression is an independent prognostic predictor for cervical cancer.

Anaplastic Lymphoma Kinase Rearrangement in Digestive Tract Cancer: Implication for Targeted Therapy in Chinese Population.

BACKGROUND: Anaplastic lymphoma kinase (ALK) rearrangements define a subgroup of lung cancer which is eligible to targeted kinase inhibition. The aim of this study is to observe the incidence rate of ALK fusion in a large cohort of Chinese digestive tract cancer patients. PATIENTS AND METHODS: Tissue microarray (TMA) was constructed from 808 digestive tract cancer cases, including 169 esophageal squamous cell carcinoma, 182 gastric cancer and 457 colorectal cancer (CRC) cases. We tested all cases for ALK expression via a fully automated immunohistochemistry (IHC) assay. The IHC-positive cases were subjected to fluorescence in situ hybridization (FISH), real-time polymerase chain reaction (qRT-PCR), target gene enrichment and sequencing for confirmation of ALK gene rearrangement and discovery of novel fusion partner. RESULTS: Among the tested cases, 2 (0.44%) CRC cases showed positive both by IHC and FISH. By qRT-PCR, EML4-ALK fusion was found in one IHC-positive CRC case. In another IHC-positive CRC case, target gene enrichment and sequencing revealed ALK was fused to a novel partner, spectrin beta non-erythrocytic 1 (SPTBN1). One gastric cancer case showed partially positive IHC result, but no fusion was found by FISH and gene sequencing. CONCLUSIONS: The incidence rate of ALK gene fusion in Chinese CRC patients was 0.44%,but not detectable in gastric and esophageal cancers. The novel SPTBN1 -ALK fusion, together with other ALK fusion genes, may become a potential target for anti-ALK therapy.

Phosphorylated AKT1 is associated with poor prognosis in esophageal squamous cell carcinoma.

BACKGROUND: The epidermal growth factor receptor (EGFR) signaling pathway is important in regulating biological behaviors in many malignancies. We explored whether expression and activation of EGFR and several components on its downstream pathways have prognostic significance in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Expression of EGFR, phosphorylated (p)-EGFR, AKT1, p-AKT1, AKT2, p-AKT2, ERK1, ERK2, p-ERK1/2, STAT3, and p-STAT3 was assessed by immunohistochemical analysis of tissue microarrays for 275 ESCC patients who had undergone complete three-field lymphadenectomy. Spearman rank correlation tests were used to determine the relationships among protein expression, and Cox regression analyses were performed to determine the prognostic factors on overall survival (OS). RESULTS: p-EGFR expression was correlated statistically with all of the other phosphorylated markers. Gender, N stage, and p-AKT1 expression were found to be independent prognostic factors for OS. Increased expression of p-AKT1 was associated with decreased patient survival. EGFR and p-EGFR expression was not significantly associated with patient survival. CONCLUSION: Activation of AKT1 was associated with poor prognosis in ESCC.

The impact of GSTM1/GSTT1 polymorphism for the risk of oral cancer.

OBJECTIVES: Since development of oral squamous cell cancer (OSCC) is triggered by various noxa, different variants of the antioxidant glutathione S-transferases (GSTs) can counteract toxic compounds (e.g., tobacco smoke). Because different polymorphisms of GST are known to have an increased sensitivity to carcinogenic agents, the aim of this study was to analyze whether GSTM1 or GSTT1 polymorphisms increase the risk for the development of OSCC. MATERIALS AND METHODS: GSTM1 and GSTT1 polymorphism was examined in healthy volunteers (n = 93) and in patients with OSCC (n = 100) by PCR after brush biopsy of oral mucosa. Odds ratio (OR) was calculated to evaluate the risk of oral cancer development. RESULTS: GSTM1 and GSTT1 deletion was found in 57% (53/93) and 18% (17/93), respectively, in healthy patients, while the OSCC group showed 57% (57/100) for GSTM1 deletion and 22% (22/100) with a deletion of GSTT1. Odds ratio for GSTM1 polymorphism was 1.00 and for GSTT1 1.26. Comparing smokers and nonsmokers with GSTM1 deletion polymorphism, OR was 4.35, while smokers without GSTM1 deletion showed an OR of 1.45. Adapting these data to the smoking habits of the general population in Germany, the OR was 9.25 for smokers with a GSTM1 deletion and OR 6.68 for smokers without a GSTM1 deletion. In smokers with GSTT1 deletion polymorphism, OR was 1.6 (adapted to the smoking habits of the general population: OR 6.16) and 3.16 (OR 8.56) in smokers without deletion in GSTT1 gene. CONCLUSIONS: Analysis of GST-M1 polymorphism in smokers could help to identify patients with a higher risk for the development of oral cancer. CLINICAL RELEVANCE: Early detection of OSCC due to a close meshed monitoring program for patients with GST-M1 polymorphism could help to improve the patient outcome. For polymorphism investigations, the oral brush biopsy is a sufficient method to gain DNA material.

ErbB4 as a potential molecular target in the treatment of esophageal squamous cell cancers.

ErbB4 is an important member of ErbB subfamily of tyrosine kinases receptor with overexpression in several tumors; however its biological role in esophageal cancer is poorly understood till date. The main objective of this study was to examine whether miRNA-140-5p could target and control ErbB4 expression at transcriptional level. The ErbB4 expressions in different cell lines were evaluated by western blotting and luciferase assay. Moreover, cell proliferation, apoptosis, and cell invasion studies were investigated using MTT, flow cytometry, and transwell assays. miRNA-140-5p remarkably downregulated the ErbB4 expression in EC9706 and TE-1A cell lines. Furthermore, miRNA-140-5p transfected cell significantly controlled the cell proliferation and enhanced the apoptosis of multiple cells. Additionally, miRNA-140-5p had marked effect on the DNA synthesis and caspase 3/7 activity in comparison to control cells. Specifically, miRNA-140-5p inhibited/repressed the cancer cell invasion and migration in a sign to have important biological role in esophageal carcinomas. Taken together, miRNA-140-5p could act as a potential molecular target in ErbB4 overexpressing ESCC cell lines paving the way for effective esophageal cancer treatment.

The oncogenic role of PKCiota gene amplification and overexpression in Chinese non-small cell lung cancer.

BACKGROUND: The atypical protein kinase C isozyme iota (PKCiota) has been proposed as an oncogene based on its transformation property and amplification identified in Caucasian non-small cell lung cancer (NSCLC) patients. Because the geography difference of some genetic aberrance such as EGFR mutations between Caucasian and Asian NSCLC patients has been identified previously, it is important to know whether the PKCiota amplification also occurs in Asian NSCLC patients. METHODS: The PKCiota gene copy number changes and protein expression in Chinese patients samples were detected by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Logistic regression was used to assess the association of PKCiota expression with clinicopathological parameters. siRNA-mediated gene silencing was applied to demonstrate the role of PKCiota in promoting cell growth in PKCiota gene amplified and protein overexpressed cancer cells. RESULTS: The result showed that PKCiota gene was amplified in 20.2% (24/119) of the tested primary tumor samples from Chinese NSCLC patients. Interestingly this gene amplification was highly enriched in squamous NSCLC patients (37.1%, 23/62). Further IHC analysis indicated that PKCiota protein was highly expressed (IHC score 2+ and 3+) in 91.6% (109/119) of Chinese NSCLC tumors. Moreover, the PKCiota gene amplification was also correlated with gender, subtype and distant metastasis. Knockdown of PKCiota gene in the PKCiota gene amplified and protein overexpressed cells led to significant growth inhibition. CONCLUSION: Taken together, our data demonstrate that PKCiota is a potential oncogene and therapeutic target in Chinese NSCLC.

FHOD1, a formin upregulated in epithelial-mesenchymal transition, participates in cancer cell migration and invasion.

Cancer cells can obtain their ability to invade and metastasise by undergoing epithelial-to-mesenchymal transition (EMT). Exploiting this mechanism of cellular plasticity, malignant cells can remodel their actin cytoskeleton and down-regulate proteins needed for cell-cell contacts. The mechanisms of cytoskeletal reorganisation resulting in mesenchymal morphology and increased invasive potential are poorly understood. Actin nucleating formins have been implicated as key players in EMT. Here, we analysed which formins are altered in squamous cell carcinoma related EMT. FHOD1, a poorly studied formin, appeared to be markedly upregulated upon EMT. In human tissues FHOD1 was primarily expressed in mesenchymal cells, with little expression in epithelia. However, specimens from oral squamous cell cancers demonstrated consistent FHOD1 upregulation in mesenchymally transformed cells at the invasive edge. This upregulation was confirmed in an oral squamous carcinoma model, where FHOD1 expression was markedly increased upon EMT in a PI3K signalling dependent manner. In the EMT cells FHOD1 contributed to the spindle-shaped morphology and mesenchymal F-actin organization. Furthermore, functional assays demonstrated that FHOD1 contributes to cell migration and invasion. Finally, FHOD1 depletion reduced the ability of EMT cancer cells to form invadopodia and to degrade extracellular matrix. Our results indicate that FHOD1 participates in cytoskeletal changes in EMT. In addition, we show that FHOD1 upregulation occurs during cancer cell EMT in vivo, which indicates that FHOD1 may contribute to tumour progression.

Emerging tyrosine kinase inhibitors for head and neck cancer.

INTRODUCTION: Conventional treatments for head and neck squamous cell cancer (HNSCC) are not completely effective and present several issues in terms of toxicity. Treatments available consist of surgery, chemoradiotherapy and biological agents. AREAS COVERED: Tyrosine-kinase inhibitors (TKIs) alone or in combination, already tested or currently under investigation, will be evaluated together with their time placement along the treatment as well as the disease setting where they were used. EXPERT OPINION: From the results of the main trials on TKIs, it emerges that these agents added to chemotherapy in recurrent/metastatic setting do not represent the best approach because of the major side effects, worsened by the complex characteristics of treated patients, and the lack of gain in terms of efficacy. Targeted agents could better exploit their activity in other settings, such as either before local regional treatment or immediately after to modulate biological effects induced by the treatment itself (surgery and/or radiation) and/or concurrently with radiation. Future research should also focus on irreversible pan-HER inhibitors, or combination agents able to overcome primary and acquired resistance, and on relevant biomarkers that would allow for a better therapeutic index of these molecules.

Loss of TAK1 increases cell traction force in a ROS-dependent manner to drive epithelial-mesenchymal transition of cancer cells.

Epithelial-mesenchymal transition (EMT) is a crucial step in tumor progression, and the TGFß-SMAD signaling pathway as an inductor of EMT in many tumor types is well recognized. However, the role of non-canonical TGFß-TAK1 signaling in EMT remains unclear. Herein, we show that TAK1 deficiency drives metastatic skin squamous cell carcinoma earlier into EMT that is conditional on the elevated cellular ROS level. The expression of TAK1 is consistently reduced in invasive squamous cell carcinoma biopsies. Tumors derived from TAK1-deficient cells also exhibited pronounced invasive morphology. TAK1-deficient cancer cells adopt a more mesenchymal morphology characterized by higher number of focal adhesions, increase surface expression of integrin α5ß1 and active Rac1. Notably, these mutant cells exert an increased cell traction force, an early cellular response during TGFß1-induced EMT. The mRNA level of ZEB1 and SNAIL, transcription factors associated with mesenchymal phenotype is also upregulated in TAK1-deficient cancer cells compared with control cancer cells. We further show that TAK1 modulates Rac1 and RhoA GTPases activities via a redox-dependent downregulation of RhoA by Rac1, which involves the oxidative modification of low-molecular weight protein tyrosine phosphatase. Importantly, the treatment of TAK1-deficient cancer cells with Y27632, a selective inhibitor of Rho-associated protein kinase and antioxidant N-acetylcysteine augment and hinders EMT, respectively. Our findings suggest that a dysregulated balance in the activation of TGFß-TAK1 and TGFß-SMAD pathways is pivotal for TGFß1-induced EMT. Thus, TAK1 deficiency in metastatic cancer cells increases integrin:Rac-induced ROS, which negatively regulated Rho by LMW-PTP to accelerate EMT.

Genetic deregulation of the PIK3CA oncogene in oral cancer.

The phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway is one of the most commonly deregulated pathways in human cancers. PI3K comprises a catalytic (p110α) and regulatory subunit (p85), and p110α is encoded by the PIK3CA gene. Here, we summarize the known genetic alterations, including amplifications and mutations, of the PIK3CA oncogene in oral cancer. We discuss in detail PIK3CA mutations and their mutual exclusivity with pathway genes in addition to the incidence of PIK3CA mutations in relation to ethnicity. We describe the constitutive activation of PI3K signaling, oncogenicity, and the genetic deregulation of the PIK3CA gene and its association with oral cancer disease stage. We emphasize the importance of therapeutically targeting the genetically deregulated PIK3CA oncogene and its signaling. We also discuss the implications of targeting Akt and/or mTOR, which are the downstream effectors of PI3K that may possibly pave the way for molecular therapeutic targets for PIK3CA-driven oral carcinogenesis. Furthermore, this critical review provides a complete picture of the PIK3CA oncogene and its deregulation in oral cancer, which may facilitate early diagnosis and improve prognosis through personalized molecular targeted therapy in oral cancer.

Single-nucleotide polymorphisms and haplotypes of membrane type 1-matrix metalloproteinase in susceptibility and clinical significance of squamous cell neoplasia of uterine cervix in Taiwan women.

Membrane type 1-matrix metalloproteinase (MT1-MMP) participates in the activity of MMP-2, which correlates with cancer of uterine cervix. Single-nucleotide polymorphisms (SNPs) in promoter and exon of MT1-MMP may influence their binding with transcription factors and gene transcription. To date, no study reports the association of the MT1-MMP polymorphisms with cervical neoplasia. Therefore, we investigated the influence of the MT1-MMP gene polymorphisms on the susceptibility and clinicopathological variables of cervical neoplasia for women in Taiwan. We recruited 72 patients with cervical squamous cell carcinoma and 63 with high-grade dysplasia as 1 subgroup. Meanwhile, 280 control women were included as another subgroup. The SNPs rs1003349 (site -165), rs2236307 (+7096), and rs3751489 (+8153) as well as rs2236302 (site +6727) of MT1-MMP gene were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism and real-time PCR genotyping, respectively. Then, we correlated these SNPs and haplotypes with the development of cervical neoplasia and cancer clinicopathological variables. We found that women with CC genotype in rs2236307 SNP exhibited a more risk to develop cervical neoplasia as compared with those with wild genotype TT. Haplotypes -165 T, +6727 C, +7096 C, +8153 G or -165 G, +6727 G, +7096 T, and +8153 G and diplotypes including at least 1 type of these haplotypes of MT1-MMP gene showed a higher risk of cervical neoplasia. However, both haplotypes were not significantly correlated with the clinicopathological characteristics of cervical cancer. In conclusion, Taiwan women with variant homozygote CC (+7096) and haplotypes, TCCG and GGTG, of MT1-MMP exhibit more risk in developing cervical neoplasia.

Genetic insight and therapeutic targets in squamous-cell lung cancer.

Squamous-cell lung cancer is one of the most prevalent subtypes of lung cancer worldwide and its pathogenesis is closely linked with tobacco exposure. Unfortunately, squamous-cell lung cancer patients do not benefit from major advances in the development of targeted therapeutics such as epidermal growth factor receptor (EGFR) inhibitors or anaplastic lymphoma kinase (ALK) inhibitors that show exquisite activity in lung adenocarcinomas with EGFR mutations or echinoderm microtubule associated protein like-4 (EML4)-ALK fusions, respectively. Major efforts have been launched to characterize the genomes of squamous-cell lung cancers. Among the new results emanating from these efforts are amplifications of the fibroblast growth factor receptor 1 gene and mutations of the discoidin domain receptor 2 gene as potential novel targets for the treatment of squamous-cell lung cancer patients. Here, we provide a review on these discoveries and their implications for clinical trials in squamous-cell lung cancer assessing the value of novel therapeutics addressing these targets.

DNA repair gene expression level in peripheral blood and tumour tissue from non-small cell lung cancer and head and neck squamous cell cancer patients.

BACKGROUND: The nucleotide excision repair pathway is crucial for cellular DNA integrity and the ERCC1 helicase is also potentially involved in resistance to platinum-based chemotherapy, and high levels of ERCC1 mRNA in tumours have been associated with cisplatin resistance in different human cancers. The aim of this work was to investigate the correlation between DNA repair gene expression levels in tumour tissue, normal tissue and peripheral blood samples from patients with two common human cancers, non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (HNSCC), to test if blood gene expression could be a proxy for tumour tissue gene expression to predict response to platinum-based chemotherapy. METHODS: Using RT-qPCR we determined ERCC1, ERCC2, ERCC4, XPA, XPC, XRCC1, XRCC3, APEX, OGG1, MGMT mRNA levels in fresh NSCLC, normal lung and HNSCC tissue, as well as blood, from NSCLC and HNSCC patients who were treated surgically. RESULTS: Target gene expression in NSCLC and HNSCC tissue was higher than in blood. A statistically significant correlation (p<0.05) was found between target gene mRNA expression in tumour tissue and blood, in particular ERCC1, MGMT, XPC, XRCC1 and XRCC3 in NSCLC and APEX, ERCC1, ERCC2, ERCC4, XRCC1 and XRCC3 in HNSCC. CONCLUSIONS: The existence of a significant correlation between blood and tumour tissue expression of some genes of clinical interest, such as ERCC1 in NSCLC and HNSCC, could allow the introduction in clinical practice of a simple test that would measure mRNA levels of DNA repair genes in peripheral blood samples instead of tissue samples to determine prognostic and predictive factors in NSCLC and HNSCC patients.

Change of telomerase activity in peripheral whole blood of head and neck squamous cell carcinoma patients before and after surgery: a pilot study.

BACKGROUND The purpose of this study was to evaluate telomerase activity in peripheral whole blood from head and neck squamous cell carcinoma (HNSCC) patients as a biomarker for diagnosis of HNSCC or detection of recurrence during follow-up. MATERIALS AND METHODS Telomerase activity was measured from peripheral whole blood extracts by telomerase repeat amplification protocol (TRAP) in HNSCC patients before and after surgery and in a control group. Sixty-two HNSCC patients and 42 control subjects were included. RESULTS Telomerase activity was found in 41 out of 62 (66.1%) HNSCC patients before surgery and in 8 out of 42 (19.0%) controls (p<0.001). Among 41 HNSCC patients who showed positive telomerase activity before surgery, 32 (78.1%) showed a conversion of telomerase activity to negative after surgery. In follow-up, 6 out of 8 (75%) showed conversion of telomerase activity from negative to positive after recurrence. Telomerase activity was changed to negative in 4 out of 6 (66%) recurred patients with positive telomerase activity after second surgery. CONCLUSION The telomerase activity in peripheral whole blood extracts of HNSCC patients might be a useful biomarker for detecting recurrence after treatment. Further study with larger sample size using a more sensitive detection method of telomerase activity is necessary to verify these results.

Change of telomerase activity in peripheral whole blood of head and neck squamous cell carcinoma patients before and after surgery: a pilot study

BACKGROUND The purpose of this study was to evaluate telomerase activity in peripheral whole blood from head and neck squamous cell carcinoma (HNSCC) patients as a biomarker for diagnosis of HNSCC or detection of recurrence during follow-up. MATERIALS AND METHODS Telomerase activity was measured from peripheral whole blood extracts by telomerase repeat amplification protocol (TRAP) in HNSCC patients before and after surgery and in a control group. Sixty-two HNSCC patients and 42 control subjects were included. RESULTS Telomerase activity was found in 41 out of 62 (66.1%) HNSCC patients before surgery and in 8 out of 42 (19.0%) controls (p<0.001). Among 41 HNSCC patients who showed positive telomerase activity before surgery, 32 (78.1%) showed a conversion of telomerase activity to negative after surgery. In follow-up, 6 out of 8 (75%) showed conversion of telomerase activity from negative to positive after recurrence. Telomerase activity was changed to negative in 4 out of 6 (66%) recurred patients with positive telomerase activity after second surgery. CONCLUSION The telomerase activity in peripheral whole blood extracts of HNSCC patients might be a useful biomarker for detecting recurrence after treatment. Further study with larger sample size using a more sensitive detection method of telomerase activity is necessary to verify these results (AU)

Protective association exhibited by the single nucleotide polymorphism (SNP) rs1052133 in the gene human 8-oxoguanine DNA glycosylase (hOGG1) with the risk of squamous cell carcinomas of the head & neck (SCCHN) among north Indians.

BACKGROUND & OBJECTIVES: Imbalances in compactly regulated DNA repair pathways in the form of single nucleotide polymorphisms (SNPs) within vital DNA repair genes may result in insufficient DNA repair and increase in DNA breaks thus rendering the human system vulnerable to the debilitatory effects of grave diseases like cancers. The present study involves investigation of association of the non-synonymous SNP rs1052133 (C8069G/Ser326Cys) located in the exonic region of the gene human 8-oxoguanine DNA glycosylase (hOGG1) with the risk of squamous cell carcinomas of the head and neck (SCCHN). METHODS: Case-control based genetic association study was performed among 575 (250 SCCHN cases and 325 normal healthy controls) sub-population cluster-matched (Indo-Europeans linguistic subgroup + Caucasoid morphological subtype) samples from the north Indian States of Uttar Pradesh and Uttarakhand using polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing analysis. RESULTS: Our results demonstrated statistically significant protective association for the heterozygous CG [Odds Ratio (OR) 0.6587, 95% Confidence Interval (CI) 0.4615 to 0.9402, P=0.0238], homozygous mutant GG (OR 0.2570, 95% CI 0.1070 to 0.6175, P=0.0013) and combined mutant CG + GG (OR 0.6057, 95% CI 0.4272 to 0.8586, P=0.0059) genotypes. INTERPRETATION & CONCLUSIONS: The results indicate that the polymorphism rs1052133 is strongly associated with SCCHN susceptibility and the mutant (G) allele might be a protective factor for SCCHN among north Indian subpopulations.

RECQL1 and WRN proteins are potential therapeutic targets in head and neck squamous cell carcinoma.

RECQL1 and WRN proteins are RecQ DNA helicases that participate in suppression of DNA hyper-recombination and repair. In this study, we report evidence supporting their candidacy as cancer therapeutic targets. In hypopharyngeal carcinomas, which have the worst prognosis among head and neck squamous cell carcinomas (HNSCC) that are rapidly rising in incidence, we found that RECQL1 and WRN proteins are highly expressed and that siRNA-mediated silencing of either gene suppressed carcinoma cell growth in vitro. Similarly, siRNA administration in a murine xenograft model of hypopharyngeal carcinoma markedly inhibited tumor growth. Moreover, combining either siRNA with cis-platinum (II) diammine dichloride significantly augmented the in vivo anticancer effects of this drug that is used commonly in HNSCC treatment. Notably, we observed no recurrence of some tumors following siRNA treatment in this model. Our findings offer a preclinical proof of concept for RECQL1 and WRN proteins as novel therapeutic targets to treat aggressive HNSCC and perhaps other cancers.

Epidermal growth factor receptor (EGFR) and squamous cell carcinoma of the skin: molecular bases for EGFR-targeted therapy.

Cutaneous squamous cell carcinoma (SCC) ranks second in the frequency of all skin tumors. Its incidence has risen significantly due to an increased sun exposure and the number of immunocompromised patients. It has a well-defined progression with known precursor lesions called actinic keratosis. The degree of cellular differentiation, tumor thickness, location, and other features has prognostic value. It has a better prognosis than mucosal SCC of the head and neck, also called head and neck squamous cell carcinoma (HNSCC). Ultraviolet light plays a fundamental role as an initiator and promoter of carcinogenesis of SCC, allowing the accumulation of genetic alterations that allows a selective growth advantage. The TP53 (p53) gene often mutates and Ras is frequently activated, but with low frequency of mutations. Normally, the extracellular signals determine whether the cells move from a quiescent state into an active proliferative state. In tumor cells an increase in the production of growth factors and its receptors can be often seen that gives rise to such an autocrine circuit facilitating cellular division. Recently, frequent mutations in the epidermal growth factor receptor (EGFR) have been detected in lung cancer, mainly deletions in exon 19 and L858R mutation in exon 21. These are located at the EGFR tyrosine kinase domain (TK). EGFR TK mutations produce activation of the signaling pathways downstream and preferentially activated antiapoptotic pathways (PI3K/AKT, JAK-STAT and ERK/MAPK). These mutations are correlated with the clinical response of patients to tyrosine kinase inhibitors (gefinitib and erlotinib), because the tumor cells are addicted to the constant activation of specific signaling pathways. Glioblastoma shows another EGFR mutation (EGFRvIII), corresponding to a deletion of the extracellular domain, and it is present in 24-67% of these tumors. This variant has been found in 42% of HNSCC, related to the poor response to monoclonal antibody cetuximab. Many observations show that there are abnormalities in the expression of epidermal growth factor receptor (EGFR) and/or its ligands in HNSCC with frequent activation of multiple pathways downstream EGFR, and unrelated to RAS mutation. This suggests the possibility of activation by mutation or overexpression of a component of the pathway located upstream-Ras. While in other tumors, especially lung cancer and glioblastoma, the EGFR mutations are frequent genetic events, it is unknown whether EGFR is mutated or amplified in SCC of the skin and what would be its pathogenic role in this malignancy and its precursors.

Immunohistochemical evaluation of COX-2 expression in HPV-positive cervical squamous intraepithelial lesions.

Cyclooxygenase 2 (COX-2) regulates the prostaglandins production and it seems to have a role in the onset and progression of different malignant tumors, being overexpressed in numerous human malignancies and premalignant conditions. Some cellular elements from chronic inflammatory processes, together with stromal cells may be involved in neoplastic transformation of proliferative stem cells and in the process of tumor invasion. Cervical carcinoma, as a commonly pattern of different tumors, can express COX-2 in association with glutathione-S-transferase isoenzymes and can be considered as possible molecular targets in antitumoral therapy. The purpose of this study was to evaluate the expression of cyclooxygenase (COX)-2 in cervical squamous intraepithelial lesions of low-grade (LSIL) and high-grade (HSIL), with morphologic evidence of HPV infection. Immunostains with COX-2 antibodies were performed on formalin-fixed and paraffin-embedded tissue sections from 20 cervical biopsies: 10 with LSIL histopathologic diagnosis and 10 with HSIL histopathologic diagnosis. All LSIL biopsies and four HSIL cases (equivalent to CIN2) presented also intermediate squamous cells, with pathognomonic morphology of HPV infection (koilocytes). The Allred immunohistochemical score for the intensity of staining and the percent of cells stained was assigned. The slides were scored by three independent pathologists and compared across histological categories. Regarding the intensity of cytoplasmic COX-2 immunostaining, a weaker expression was observed in specimens with LSIL and a stronger one in those diagnosed with HSIL, the highest score being noted in HSIL corresponding to CIN3 lesions. The increase of COX-2 expression in cervical cancer precursors certifies that COX-2 may have a role in the development and progression of cervical squamous intraepithelial lesions.