ERCC1 and personalized medicine in lung cancer

Inhibition of DNA‑PK by gefitinib causes synergism between gefitinib and cisplatin in NSCLC

Lung cancer has the highest incidence and mortality rates among the malignant tumor types worldwide. Platinum‑based chemotherapy is the main treatment for advanced non‑small‑cell lung cancer (NSCLC), and epidermal growth factor receptor‑tyrosine kinase inhibitors (EGFR‑TKIs) have greatly improved the survival of patients with EGFR‑sensitive mutations. However, there is no standard therapy for treating patients who are EGFR‑TKI resistant. Combining EGFR‑TKIs and platinum‑based chemotherapy is the most popular strategy in the clinical practice. However, the synergistic mechanism between EGFR‑TKIs and platinum remains unknown. Therefore, the aim of the present study was to determine the synergistic mechanism of gefitinib (an EGFR‑TKI) and cisplatin (a main platinum‑based drug). MTT assay, apoptosis analysis, tumorsphere formation and an orthotropic xenograft mouse model were used to examine the combination effects of gefitinib and cisplatin on NSCLC. Co‑immunoprecipitation and immunofluorescence were used to identify the underlying mechanism. It was found that gefitinib could selectively inhibit EGFR from entering the nucleus, decrease DNA‑PK activity and enhance the cytotoxicity of cisplatin on NSCLC. Collectively, the results suggested that inhibition of DNA‑dependent protein kinase by gefitinib may be due to the synergistic mechanism between gefitinib and cisplatin. Thus, the present study provides a novel insight into potential biomarkers for the selection of combination therapy of gefitinib and cisplatin.

Elucidating the role of excision repair cross-complement group 1 in oral epithelial dysplasia and early invasive squamous cell carcinoma: An immunohistochemical study

Objectives:

Oral epithelial dysplasia (OED) is characterized by cellular alterations which have the proclivity of progressing to squamous cell carcinoma. Excision repair cross-complement group 1 (ERCC1) is one of the key proteins involved in nucleotide excision repair (NER) pathway. The expression of ERCC1 has been studied in colorectal, esophageal, ovarian and oral squamous cell carcinoma; but, very few studies have been done to apprehend the expression of ERCC1 in OED and early invasive squamous cell carcinoma (EISCC). The goal of this study is to evaluate the role of ERCC1 in OED and EISCC.

Materials and Methods:

Histopathologically diagnosed cases of moderate dysplasia (n = 10), severe dysplasia (n = 10) and EISCC (n = 10) were retrieved. 4 μ thick sections were cut from the formalin-fixed paraffin-embedded tissue blocks. The sections were immunohistochemically stained for ERCC1 following standard protocols. The expression of ERCC1 was evaluated semiquantitatively. Statistical analysis was carried out using Fischer's exact t-test.

Results:

The expression of ERCC1 was found to be strong (+3) in EISCC, moderate (+2) in severe dysplasia and mild (+1) in moderate dysplasia. Thus, the results were statistically significant between the three groups (P < 0.001).

Conclusion:

Disruption in the mechanisms that regulate cell cycle checkpoints and DNA repair mechanism results in genomic instability; these alterations might contribute to carcinoma. ERCC1 is essential to repair the DNA damage induced by various carcinogens. The present study shows significant difference in the expression of ERCC1 between EISCC and OED, which suggests ERCC1 could be used as one of the predictive markers.

Quantile Graphical Models: Bayesian Approaches

Graphical models are ubiquitous tools to describe the interdependence between variables measured simultaneously such as large-scale gene or protein expression data. Gaussian graphical models (GGMs) are well-established tools for probabilistic exploration of dependence structures using precision matrices and they are generated under a multivariate normal joint distribution. However, they suffer from several shortcomings since they are based on Gaussian distribution assumptions. In this article, we propose a Bayesian quantile based approach for sparse estimation of graphs. We demonstrate that the resulting graph estimation is robust to outliers and applicable under general distributional assumptions. Furthermore, we develop efficient variational Bayes approximations to scale the methods for large data sets. Our methods are applied to a novel cancer proteomics data dataset where-in multiple proteomic antibodies are simultaneously assessed on tumor samples using reverse-phase protein arrays (RPPA) technology.

Low ERCC1 expression is a good predictive marker in lung adenocarcinoma patients receiving chemotherapy based on platinum in all TNM stages - a single-center study

BACKGROUND

High ERCC1 expression is thought to be related with resistance to chemotherapy based on platinum. The aim of this study was to present our institutional observations regarding to the association of ERCC1 and overall survival (OS) of the lung adenocarcinoma patients who received chemotherapy based on platinum.

MATERIAL/METHODS

A total of 253 lung adenocarcinoma patients in all TNM stages were retrospectively investigated. The diagnosis was based on small biopsy samples obtained during bronchoscopy. Depending on the TNM stage of the disease and clinical condition, patients received only the chemotherapy based on platinum, or in combination with radiotherapy or surgery. Tissue sample for ERCC1 immunohistochemical analysis was sufficient in 129 patients. Low from high ERCC1 expression was separated by the semi-quantitative H-score median.

RESULTS

High ERCC1 expression was found in 47.3% patients, and was correlated with higher TNM (p = 0.021), tumor enlargement (p = 0.002), positive lymph nodes (p = 0.001), positive distant metastasis (p = 0.005), and higher relative risk of death (p < 0.001). Furthermore, significance association was observed for low ERCC1 expression and better performance status (ECOG) (p = 0.023). Longer OS was strongly associated with a low ERCC1 expression, not only in the group of patients in TNM stage I-III, who were treated with combination of chemotherapy with surgery or radiotherapy (p = 0.002), but also in the group of patients in TNM stage IV who received only chemotherapy based on platinum (p < 0.001), compared with the patients in the same TNM stage and high ERCC1 expression.

CONCLUSIONS

ERCC1 expression in lung adenocarcinoma is a useful prognostic marker and moreover, a useful predictive marker in patients receiving chemotherapy based on platinum in all stages of the disease.

The Utility of Thyroid Transcription Factor 1 (TTF-1), Napsin A, Excision Repair Cross-Complementing 1 (ERCC1), Anaplastic Lymphoma Kinase (ALK) and the Epidermal Growth Factor Receptor (EGFR) Expression in Small Biopsy in Prognosis of Patients with Lung Adenocarcinoma - A Retrograde Single-Center Study from Croatia

Background

The present study was carried out in order to evaluate our institutional experience with small biopsy in diagnosis and molecular testing of lung adenocarcinoma. Few specific and predictive markers have been evaluated and correlated with clinicopathologic characteristics and survival in patients with lung adenocarcinoma who received platinum-based chemotherapy. There have not been such reports from Croatia.

Material/Methods

A total of 142 cases of lung adenocarcinoma were retrospectively investigated in small biopsies for the immunohistochemical expression of TTF-1, napsin A, ERCC1, ALK, and the EGFR mutation by real-time polymerase chain reaction (rtPCR).

Results

TTF-1, napsin A, and ERCC1 expression was found in 81%, 78%, and 69% of patients, respectively, and the expressions were not significantly associated with subtype. Expression of ALK was found in 4% and EGFR mutation in 10% of patients. Exon 19 deletions were the most common. Longer survival was significantly associated with TTF-1 positivity (p=0.007) and napsin A positivity (p=0.026). Higher relative risk of death significantly correlated with positive expression of ERCC1 (p=0.041).

Conclusions

Positive TTF-1 and napsin A expressions in lung adenocarcinoma tissues were useful diagnostic and favorable prognostic parameters. Positive ERCC1 expression was identified as a negative prognostic marker in patients treated with platinum-based chemotherapy. The percentages of EGFR and ALK mutations corresponded to those in previously published reports for Caucasians.

Clinical features and mutation status of EGFR, KRAS, BRAF, EML4-ALK and ROS1 between surgical resection samples and non surgical resection samples in lung cancer

BACKGROUND

Target therapy is the first-line treatment in lung cancer. The testing of driver gene mutations is crucial for decision of treatment. Many lung cancer patients are in advanced grade, and lose the chance of operation.

METHODS

The tissue used to perform mutation testing is only from biopsy. In order to analysis the difference between surgical resection samples (SRSs) and non-surgical resection samples (NSRSs), 1,357 surgical tissues and 145 biopsy samples histopathologically diagnosed with lung cancer were collected to detect the mutation status of EGFR, KRAS, BRAF, EML4-ALK and ROS1 in this study.

RESULTS

There were no significant differences of age, gender, and histological type between the two group patients we collected; however, the significant difference was present in grade. More early stage patients were in the surgical group, but more advanced stage lung cancer patients were in non surgical group. In the mutation analysis, we also found no significant differences in all driver genes we detected between the two groups.

CONCLUSIONS

Both surgical resection samples and biopsy samples could be used to perform the testing the driver gene mutation.

Dysregulation of PAK1 Is Associated with DNA Damage and Is of Prognostic Importance in Primary Esophageal Small Cell Carcinoma

Primary esophageal small cell carcinoma (PESCC) is a rare, but fatal subtype of esophageal carcinoma. No effective therapeutic regimen for it. P21-activated kinase 1 (PAK1) is known to function as an integrator and an indispensable node of major growth factor signaling and the molecular therapy targeting PAK1 has been clinical in pipeline. We thus set to examine the expression and clinical impact of PAK1 in PESCC. The expression of PAK1 was detected in a semi-quantitative manner by performing immunohistochemistry. PAK1 was overexpressed in 22 of 34 PESCC tumors, but in only 2 of 18 adjacent non-cancerous tissues. Overexpression of PAK1 was significantly associated with tumor location (p = 0.011), lymph node metastasis (p = 0.026) and patient survival (p = 0.032). We also investigated the association of PAK1 with DNA damage, a driven cause for malignancy progression. γH2AX, a DNA damage marker, was detectable in 18 of 24 (75.0%) cases, and PAK1 expression was associated with γH2AX (p = 0.027). Together, PAK1 is important in metastasis and progression of PESCC. The contribution of PAK1 to clinical outcomes may be involved in its regulating DNA damage pathway. Further studies are worth determining the potentials of PAK1 as prognostic indicator and therapeutic target for PESCC.