KRAS and BRAF mutations predict primary resistance to imatinib in gastrointestinal stromal tumors

PURPOSE

Gastrointestinal stromal tumors (GIST) are characterized by gain-of-function mutations in KIT/PDGFRA genes leading to a constitutive receptor activation which is well counteracted by imatinib. However, cases in which imatinib as first-line treatment has no effects are reported (primary resistance). Our purpose is to investigate alterations in downstream effectors, not reported so far in mutated GIST, possibly explaining the primary resistance to targeted treatments.

EXPERIMENTAL DESIGN

Two independent naive GIST cohorts have been analyzed for KIT, PDGFRA, KRAS, and BRAF mutations by direct sequencing. Cell lines expressing a constitutively activated and imatinib-responding KIT, alone or in combination with activated KRAS and BRAF, were produced and treated with imatinib. KIT receptor and its downstream effectors were analyzed by direct Western blotting.

RESULTS

In naive GISTs carrying activating mutations in KIT or PDGFRA a concomitant activating mutation was detected in KRAS (5%) or BRAF (about 2%) genes. In vitro experiments showed that imatinib was able to switch off the mutated receptor KIT but not the downstream signaling triggered by RAS-RAF effectors.

CONCLUSIONS

These data suggest the activation of mitogen-activated protein kinase pathway as a possible novel mechanism of primary resistance to imatinib in GISTs and could explain the survival curves obtained from several clinical studies where 2% to 4% of patients with GIST treated with imatinib, despite carrying KIT-sensitive mutations, do not respond to the treatment.

ERCC1 predicts outcome in patients with gastric cancer treated with adjuvant cisplatin-based chemotherapy

BACKGROUND

Adjuvant chemotherapy is gaining an increasing role in resectable gastric cancer. Customizing chemotherapy on the basis of chemosensitivity may improve outcome, and putative predictive molecular markers have been mostly evaluated in Asian patients. We profiled key DNA and damage signaling factors and correlated them with outcome, in a European cohort.

METHODS

Formalin-fixed tumor samples obtained from surgical specimens of patients treated with adjuvant cisplatin-based chemotherapy for gastric cancer were analyzed. Immunohistochemistry (IHC) was performed to analyze excision repair cross-complementing gene 1 (ERCC1) and thymidylate synthase (TS) expression, and p53 mutations were detected with direct sequencing.

RESULTS

Among the 68 patient recruited, the median age was 69 (range 30-74), and UICC stage was III in 44 patients (65 %). With a median follow-up of 40.5 months, disease-free and overall survival were 18.0 (95 % CI 13.4-22.76) and 56 months (95 % CI 44.87-67.13), respectively. ERCC1 score was 0 in 14 out 67 (21 %) cases, 1 in 19 (28 %), 2 in 20 (30 %) and 3 in 14 cases (21 %). Longer overall survival (p = 0.04) was found in patients categorized as ERCC1 negative by IHC according to median score. TS score was 0 in 16 out 67 (24 %) cases, 1 in 27 (40 %), 2 in 16 (24 %) and 3 in 8 cases (12 %). Mutations of p53 were found in 21 out 66 (32 %) cases. Neither TS nor p53 were found to correlate with outcome.

CONCLUSION

Excision repair cross-complementing gene 1 by IHC might predict patients more likely to benefit from adjuvant cisplatin-based chemotherapy in curatively resected gastric cancer. In patients exhibiting ERCC1 positive tumors, alternative regimens should be evaluated.

Circulating Free DNA in a Screening Program for Early Colorectal Cancer Detection

Aims and Background

The quantification and molecular characterization of circulating free DNA (cfDNA) have attracted much interest as new and promising, noninvasive means of detecting and monitoring the presence of surgical resectable colorectal cancer (CRC). Instead, the role of cfDNA in the early detection of malignant and premalignant colorectal lesions is still unclear. The aim of this study was to evaluate the predictive power of the quantification and KRAS status of cfDNA in detecting early colorectal lesions in plasma from healthy high-risk subjects.

Methods

The study population consisted of 170 consecutive healthy high-risk subjects aged >50 years who participated in the screening program promoted by the Local Health Service (ASL-Milano) for early CRC detection and who underwent endoscopic examination after being found positive at fecal occult blood test (FOBT). Thirty-four participants had malignant lesions consisting of 12 adenocarcinomas (at an early stage in half of the cases) and 22 instances of high-grade intraepithelial neoplasia (HGIN) in adenomas; 73 participants had premalignant lesions (adenomas and hyperplasia), and 63 participants had no lesions. Plasma cfDNA was quantified by quantitative real-time PCR and analyzed for KRAS mutations by a mutant-enriched PCR. KRAS status was assessed also in matched adenocarcinoma and HGIN tissues. The distribution of cfDNA concentrations among FOBT-positive subjects with diagnosed lesion (cases) was compared with that of FOBT-positive subjects without lesions (controls) and its predictive capability (AUC) was assessed.

Results

The predictive capability of cfDNA levels was satisfactory in predicting adenocarcinomas (AUC 0.709; 95% CI, 0.508–0.909) but not HGIN and premalignant lesions. The rate of KRAS mutations in plasma was low (5/170 = 3%) compared with the rate observed in the matched adenocarcinoma and HGIN tissues (45%).

Conclusions

The use of cfDNA quantification to predict adenocarcinoma at an early stage in high-risk (aged >50 years and FOBT positive) subjects seems to be promising but needs more sensitive methods to improve cfDNA detection.

Partial beneficial effects of the so called "silent iodine prophylaxis" on iodine deficiency disorders (IDD) in northeastern Sicily endemia

The prevalence of goiter among schoolchildren and the daily urinary iodine excretion in the general population were evaluated in 4 municipalities in the endemic goiter area in Northeastern Sicily in two different surveys. The first, carried out in 1977-1978, covered 2,493 (91%) schoolchildren; the second, in 1987-1988, covered 2,167 (92%) schoolchildren. A dramatic decrease in goiter prevalence was apparent in each community as follows: in Castell'Umberto (3,904 inhabitants, altitude 641/750 m above sea level) goiter prevalence (G) decreased from 79.7% to 44.2% with a percent reduction (%r) of 44.5 and an increase in 24-h urinary iodine excretion (UIE) from 22.3 +/- 16.4 micrograms/24 h (n = 30) to 48.7 +/- 43.4 (n = 50). A similar trend was apparent in Tortorici (10,194 inhabitants, 475/700 m) where G decreased from 62.2 to 26.5% (% r 57.4) with a UIE increase from 28.4 +/- 29.6 (n = 35) to 47.6 +/- 59.3 (n = 40); in Sinagra (3,387 inhabitants, 300 m) where G decreased from 61.6 to 32.7% (% r 46.9) and UIE increased from 26.0 +/- 21.1 (n = 25) to 66.6 +/- 69.6 (n = 102) and in Sant'Angelo di Brolo (5,732 inhabitants, 380 m) where G decreased from 48.7 to 27.5% (% r 43.5) and UIE increased from 26.3 +/- 16.7 (n = 30) to 47.7 +/- 73.8 (n = 34). These events are clearly related and certainly dependent on the changed alimentary habits in the area due to the improved distribution of frozen food and industrially prepared dairy products, eventually enriched by iodine.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating free DNA in a screening program for early colorectal cancer detection

AIMS AND BACKGROUND

The quantification and molecular characterization of circulating free DNA (cfDNA) have attracted much interest as new and promising, noninvasive means of detecting and monitoring the presence of surgical resectable colorectal cancer (CRC). Instead, the role of cfDNA in the early detection of malignant and premalignant colorectal lesions is still unclear. The aim of this study was to evaluate the predictive power of the quantification and KRAS status of cfDNA in detecting early colorectal lesions in plasma from healthy high-risk subjects.

METHODS

The study population consisted of 170 consecutive healthy high-risk subjects aged >50 years who participated in the screening program promoted by the Local Health Service (ASL-Milano) for early CRC detection and who underwent endoscopic examination after being found positive at fecal occult blood test (FOBT). Thirty-four participants had malignant lesions consisting of 12 adenocarcinomas (at an early stage in half of the cases) and 22 instances of high-grade intraepithelial neoplasia (HGIN) in adenomas; 73 participants had premalignant lesions (adenomas and hyperplasia), and 63 participants had no lesions. Plasma cfDNA was quantified by quantitative real-time PCR and analyzed for KRAS mutations by a mutant-enriched PCR. KRAS status was assessed also in matched adenocarcinoma and HGIN tissues. The distribution of cfDNA concentrations among FOBT-positive subjects with diagnosed lesion (cases) was compared with that of FOBT-positive subjects without lesions (controls) and its predictive capability (AUC) was assessed.

RESULTS

The predictive capability of cfDNA levels was satisfactory in predicting adenocarcinomas (AUC 0.709; 95% CI, 0.508-0.909) but not HGIN and premalignant lesions. The rate of KRAS mutations in plasma was low (5/170 = 3%) compared with the rate observed in the matched adenocarcinoma and HGIN tissues (45%).

CONCLUSIONS

The use of cfDNA quantification to predict adenocarcinoma at an early stage in high-risk (aged >50 years and FOBT positive) subjects seems to be promising but needs more sensitive methods to improve cfDNA detection.

Influence of KRAS mutations on outcome in patients with curatively resected stage III colon cancer treated with adjuvant chemotherapy

e14536

Background: Adjuvant chemotherapy improves survival in patients with stage III colon cancer (CC) after curative resection, and oxaliplatin in combination with fluoropyrimidine-based regimens has been established as a standard treatment. KRAS mutations could predict oxaliplatin sensitivity in CC cells, as recently demonstrated. Here, we profiled KRAS and correlated it with outcome in stage III CC patients who underwent adjuvant chemotherapy. Methods: Eligible patients were those with resected stage III CC who underwent 6-months adjuvant chemotherapy, either with single-agent fluoropyrimidine (FP: modulated 5FU or capecitabine) or with oxaliplatin-based regimens (O-FP: FOLFOX or XELOX). DNA extraction was performed on formalin-fixed paraffin-embedded sections, and KRAS mutations were analyzed by direct sequencing. Disease-free survival (DFS) and overall survival (OS) analyses were computed using the Kaplan-Meier method and the Log-rank test. Results: The study population included 261 patients: 115 treated with FP, 146 O-FP. We identified KRAS mutations in 71/261 (27.4%) cases, of which 33 (46.5%) received FP, and 38 (53.5%) O-FP. In wild-type (wt) KRAS cases, DFS and OS group did not significantly differ between the two treatment modalities [in months, FP vs O-FP - median OS: 62.0 vs 49.6, HR: 1.12 (95% CI: 0.65; 1.92); median DFS: 57.1 vs 44.4, HR: 0.93 (95% CI: 0.55; 1.56)]. In patients treated with FP, a worse DFS [in months, mutant vs wt - median DFS: 46.0 vs 57.1, p=0.04; HR: 1.86 (95% CI: 1.01; 3.41)] and a trend toward a worse OS in months, mutant vs wt - median OS: 56.1 vs 62.0, p=0.08; HR: 1.71 (95% CI: 0.94; 3.10)] were observed in KRAS mutated patients. On the contrary, DFS and OS were not statistically different for mutated and wt KRAS patients treated with O-FP [in months, mutant vs wt - median DFS: 43.7 vs 44.4, p=0.62; HR: 1.17 (95% CI: 0.63; 2.18); median OS: 48.9 vs 49.6, p=0.77; HR: 1.11 (95% CI: 0.55; 2.23). Conclusions: Our results suggest that curatively resected stage III CC patients exhibiting wt KRAS status might benefit from FP alone. On the contrary, an oxaliplatin-containing regimen should be recommended in KRAS mutated patients.

Exploring the Potential Impact of Training on Short-Term Quality of Life and Stress of Parents of Children with Autism: The Integrative Parents' Autism Training Module

Parents of autistic children experience high levels of parental stress and low quality of life related to the demanding child caring burden they experience. Parent education and training programs are acknowledged to improve parental well-being and reduce parenting stress. In the framework of the Erasmus+ Integrative Autism Parents Training Project (IPAT), we developed the IPAT Training Module based on parents' expressed needs, in order to improve parental quality of life (QoL) and decrease their perceived stress. Sixty-two parents from four countries participated in the IPAT Module Training activity. We used WHOQOL-BREF and Perceived Stress Scale (PSS-10 version) for QoL and stress, respectively, before and after training and a study-specific questionnaire to assess participants' satisfaction. Parents' QoL improved significantly in the environment domain and specific items, while stress levels remained unmodified. Training appeared more advantageous for parents with lower initial QoL and those whose child had been enrolled in a special education program for an extended duration. Parents were quite satisfied, in particular those with lower initial social relationships QoL. Larger studies including a control group are necessary to support preliminary evidence provided by this study, identify additional effect moderators, and disentangle the contribution of different components of the training.

Influence of KRAS mutations on clinical outcome in patients with curatively resected stage III colon cancer treated with adjuvant chemotherapy

OBJECTIVE

To profile and correlate KRAS mutations with outcome in stage III colon cancer (CC) patients who underwent adjuvant chemotherapy following curative resection surgery.

PATIENTS AND METHODS

In this retrospective study, eligible patients were those with resected stage III CC who underwent 6-months adjuvant chemotherapy, either with fluoropyrimidine monotherapy (FP) or with oxaliplatin-based regimens (O-FP). Disease-free survival (DFS) and overall survival (OS) were analyzed and computed using the Kaplan-Meier method and the log-rank test.

RESULTS

The study population included 148 patients (n=65 FP and n=83 O-FP). We identified KRAS mutations in 41/148 (27%) patients, of which 18 (44%) received FP and 23 (56%) O-FP. Five-year DFS and OS were significantly higher in patients with KRAS wild-type vs. mutant [DFS: 78 vs. 56%, HR: 0.47 (95% CI: 0.25; 0.87), p=0.01; OS: 73 vs. 68%, HR: 0.44 (95% CI: 0.21; 0.88), p=0.01]. In patients treated with FP, the 5-year DFS and OS was significantly improved in the KRAS wild-type vs. mutant group, respectively [DFS: 80 vs. 43%, HR: 2.88 (95% CI: 0.67; 3.76), p=0.014; OS: 85 vs. 68%, HR: 0.27 (95% CI: 0.10; 0.73), p=0.005]. Conversely, 5-year DFS and OS were not statistically different for patients with KRAS wild-type vs. mutations treated with O-FP, respectively [DFS: 78 vs. 65%, HR: 1.59 (95% CI: 0.67; 3.76), p=0.281; OS: 80 vs. 75%, HR: 0.73 (95% CI: 0.55; 2.12), p=0.57)].

CONCLUSIONS

Our results suggest that curatively resected stage III CC patients exhibiting wild-type KRAS status might benefit from FP alone. Conversely, an oxaliplatin-containing regimen should be recommended in KRAS mutated patients.