Extended RAS analysis and correlation with overall survival in advanced pancreatic cancer.

BACKGROUND: Mutations in the KRAS gene can be detected in about 70-90% of pancreatic cancer (PC) cases. Whether these mutations have a prognostic or predictive value remains elusive. Furthermore, the clinical relevance of the extended RAS (KRAS+NRAS) mutational status is unclear in PC. METHODS: We prospectively defined a PC patient population who received erlotinib-free chemotherapy regimens. A statistically significant difference between KRAS wild-type and KRAS mutated tumours in at least 160 patients in this population would support the assumption of a rather prognostic role of KRAS. RESULTS: One hundred and seventy-eight tumour samples were collected from prospective clinical studies and successfully analysed for the extended RAS status: 37 tumours were KRAS wild-type (21%), whereas 141 (79%) carried a KRAS mutation; 132 of these mutations were found in KRAS exon 2 (74%), whereas only 9 mutations (5%) were detected in KRAS exon 3. Within KRAS exon 4 and NRAS exons 2-4, no mutations were apparent. There was no significant difference in overall survival for KRAS wild-type vs mutant patients (9.9 vs 8.3 months, P=0.70). CONCLUSIONS: Together with the results of the AIO-PK-0104-trial, the present analysis supports the notion that KRAS mutation status is rather predictive than prognostic in advanced PC.

Switch in KRAS mutational status during an unusual course of disease in a patient with advanced pancreatic adenocarcinoma: implications for translational research.

BACKGROUND: Despite the introduction of novel effective treatment regimens like gemcitabine plus nab-paclitaxel and FOLFIRINOX, pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive epithelial tumors. Among the genetic alterations frequently found in PDAC, mutations in the KRAS gene might play a prognostic role regarding overall survival and may also have the potential to predict the efficacy of anti-EGFR treatment. CASE PRESENTATION: We report the clinical case of a 69 year old Caucasian female that was diagnosed with histologically confirmed locally advanced PDAC with lymph node involvement in August 2010. At the time of first diagnosis, tumor tissue obtained from an open regional lymph node biopsy showed a poorly differentiated adenocarcinoma with a wild type sequence within exon 2 (codon 12/13) of the KRAS gene. The patient initially received single-agent gemcitabine and a subsequent 5-FU-based chemoradiotherapy with a sequential maintenance chemotherapy with oral capecitabine resulting in a long term disease control. Local disease progression occurred in May 2014 and the patient underwent pancreaticoduodenectomy in September 2014. A novel KRAS gene mutation (c.35G > T, p.G12 V) in exon 2 (codon 12) was detected within the surgical specimen. As of January 2016 the patient is still alive and without evidence of the underlying disease. CONCLUSIONS: Specifically in the context of clinical trials and translational research in PDAC a re-assessment of molecular biomarkers, i. e. KRAS, at defined time points (e. g. relapse, disease progression, unusual clinical course) may be indicated in order to detect a potential switch in biomarker status during the course of disease.

The Impact of SMAD4 Loss on Outcome in Patients with Advanced Pancreatic Cancer Treated with Systemic Chemotherapy.

The role of the tumor suppressor mothers against decapentaplegic homolog 4 (SMAD4) has not yet been defined in patients (pts) with advanced pancreatic cancer (aPC). This translational research study was designed to evaluate the impact of tumoral SMAD4 loss on clinicopathological parameters and outcome in PC patients receiving palliative chemotherapy. Using immunohistochemistry, we examined SMAD4 expression in tumor tissue of 143 aPC pts treated within completed prospective clinical and biomarker trials. In uni- and multivariate analyses, SMAD4 expression status was correlated to clinicopathological patient characteristics and outcome. At chemotherapy initiation, 128 pts had metastatic PC; most pts (n = 99) received a gemcitabine-based regimen. SMAD4 loss was detected in 92 pts (64%); patient characteristics such as gender, age, tumor grading, disease stage or number of metastatic sites had no significant impact on tumoral SMAD4 status. In univariate analyses, SMAD4 loss had no impact on overall survival (hazard ratio (HR) 1.008, p = 0.656); however, we observed a prolonged progression-free survival (HR 1.565, p = 0.038) in pts with tumoral SMAD4 loss. This finding was confirmed in multivariate analyses (HR 1.790, p = 0.040), but only for gemcitabine-treated pts. In contrast to previous studies in resectable PC, loss of SMAD4 expression was not associated with a negative outcome in patients with advanced PC receiving systemic chemotherapy.

Impact of SPARC expression on outcome in patients with advanced pancreatic cancer not receiving nab-paclitaxel: a pooled analysis from prospective clinical and translational trials.

BACKGROUND: Conflicting results on the role of secreted protein acidic and rich in cysteins (SPARC) expression have been reported in resected pancreatic ductal adenocarcinoma (PDAC), and its prognostic and/or predictive role in advanced PDAC (aPDAC) has not been extensively investigated yet. This study was designed to evaluate SPARC expression as a biomarker in aPDAC patients (pts) not receiving nab-paclitaxel. METHODS: Using immunohistochemistry, we examined the stromal as well as the tumoral (i.e., cytoplasmic) SPARC expression in tumour tissue (primary tumours and metastases) of 134 aPDAC pts participating in completed prospective clinical and biomarker trials. The SPARC expression levels were correlated to the pts' clinicopathological parameters and survival times. RESULTS: Sixty-seven per cent of the analysed tumours showed high stromal SPARC expression, which was not associated with overall survival (OS, median 9.1 vs 7.6 months, P=0.316). A positive cytoplasmic SPARC expression was detected in 55% of the tumours and correlated significantly with inferior progression-free survival (PFS, 6.2 vs 8.6 months, P=0.004) and OS (7.8 vs 8.4 months, P=0.032). This association was strongest for pts, where primary tumour tissue was examined (PFS: 6.7 vs 10.8 months, P=0.004; OS: 7.9 vs 11.9 months, P=0.030), whereas no significant correlation was detected for pts, where only metastatic tissue was available (PFS: 5.8 vs 6.6 months, P=0.502; OS: 7.0 vs 7.8 months, P=0.452). In pts receiving gemcitabine-based chemotherapy cytoplasmic SPARC expression was significantly associated with an inferior PFS and OS (PFS: 6.2 vs 9.2 months, P=0.002; OS 7.3 vs 9.9 months, P=0.012), whereas no such association was detected for stromal SPARC expression or for pts receiving fluoropyrimidine-based chemotherapy. CONCLUSION: We identified cytoplasmic SPARC expression in the primary tumour as a biomarker associated with inferior PFS and OS in aPDAC. Cytoplasmic SPARC expression may furthermore act as a negative predictive biomarker in pts treated with gemcitabine-based chemotherapy.