B-RAF and N-RAS Mutations Are Preserved during Short Time In Vitro Propagation and Differentially Impact Prognosis

In melanoma, the RAS/RAF/MEK/ERK signalling pathway is an area of great interest, because it regulates tumor cell proliferation and survival. A varying mutation rate has been reported for B-RAF and N-RAS, which has been largely attributed to the differential source of tumor DNA analyzed, e.g., fixed tumor tissues or in vitro propagated melanoma cells. Notably, this variation also interfered with interpreting the impact of these mutations on the clinical course of the disease. Consequently, we investigated the mutational profile of B-RAF and N-RAS in biopsies and corresponding cell lines from metastatic tumor lesions of 109 melanoma patients (AJCC stage III/IV), and its respective impact on survival. 97 tissue biopsies and 105 biopsy-derived cell lines were screened for B-RAF and N-RAS mutations by PCR single strand conformation polymorphism and DNA sequencing. Mutations were correlated with patient survival data obtained within a median follow-up time of 31 months. B-RAF mutations were detected in 55% tissues and 51% cell lines, N-RAS mutations in 23% tissues and 25% cell lines, respectively. There was strong concordance between the mutational status of tissues and corresponding cell lines, showing a differing status for B-RAF in only 5% and N-RAS in only 6%, respectively. Patients with tumors carrying mutated B-RAF showed an impaired median survival (8.0 versus 11.8 months, p = 0.055, tissues; 7.1 versus 9.3 months, p = 0.068, cell lines), whereas patients with N-RAS-mutated tumors presented with a favorable prognosis (median survival 12.5 versus 7.9 months, p = 0.084, tissues; 15.4 versus 6.8 months, p = 0.0008, cell lines), each in comparison with wildtype gene status. Multivariate analysis qualified N-RAS (p = 0.006) but not B-RAF mutation status as an independent prognostic factor of overall survival. Our findings demonstrate that B-RAF and N-RAS mutations are well preserved during short term in vitro propagation and, most importantly, differentially impact the outcome of melanoma patients

Use of an integrated strip-free blood glucose monitoring system increases frequency of self-monitoring and improves glycemic control: Results from the ExAct study

Aims We investigated the impact of using an integrated, strip-free system compared to the use of single-strip systems on testing frequency and glycemic control in individuals with insulin-treated diabetes. Methods This multinational, comparative, cluster-randomized, observational study included 311 patients with type 1 and insulin-treated type 2 diabetes who were performing SMBG at suboptimal frequencies. Sites were cluster-randomized to “integrated strip-free” system (EXP group) or any “single-strip” system (CNL group). Testing frequency and HbA1c were measured at baseline, 12 weeks and 24 weeks. Results At week 24, the EXP group showed an increase in SMBG frequency from baseline of 4.17 tests/week (95% CI 2.76, 5.58) compared with an increase of 0.53 tests/week (95% CI −0.73, 1.79) among CNL patients, resulting in a between-group difference of 3.63 tests/week (p < 0.0002). Mixed-effects models for repeated measurements (MMRM) controlling for baseline frequency of testing, country and clinical site confirmed a higher SMBG testing frequency in the EXP group compared to the CNL group, with a between-group difference of 2.70 tests/week (p < 0.01). Univariate analysis showed greater HbA1c reductions in the EXP group than CNL group: −0.44% (95% CI −0.59, −0.29) vs. −0.13% (95% CI −0.27, 0.01), respectively, p < 0.0002. MMRM analyses confirmed these HbA1c reductions. A greater percentage of EXP than CNL patients achieved HbA1c reductions of ≥0.5%: 45.1% vs. 29.1%, respectively, p < 0.01. Conclusions The use of an integrated, strip-free SMBG system improved testing adherence and was associated with improvements in glycemic control

Kaplan-Meier survival estimation for stage IV patients only by mutational status.

<p>Curves showing the overall survival starting with the time point of tumor biopsy in 82 metastatic melanoma patients who were in stage IV disease at that time. Survival probabilities were compared by the mutational status of B-RAF in tumor tissue biopsies (n = 70) (A) and biopsy-derived tumor cell lines (n = 80) (D), as well as N-RAS in tumor tissue biopsies (n = 70) (B) and biopsy-derived tumor cell lines (n = 80) (E). (C) and (F) differentiate patients harbouring B-RAF mutations (n = 43, tissues; n = 45, cell lines), patients harbouring N-RAS mutations (n = 12, tissues; n = 15; cell lines), and patients without mutations in both genes (n = 15, tissues; n = 20, cell lines). Statistical differences between groups were calculated using the log-rank test. Vertical bars indicate censored observations.</p

Detection and identification of B-RAF and N-RAS mutations in melanoma cell lines and corresponding tissues by fluorescent capillary electrophoresis SSCP and DNA sequencing.

<p>Migration patterns under non-denaturing conditions of single stranded fragments of exon 15 of the B-RAF gene with a T1799A mutation at codon 600 in the cell line Ma-Mel-36 (A) and the corresponding tumor tissue (B). Migration patterns for the B-RAF exon 15 fragments with wild type sequences in the cell line Ma-Mel-37a (C) and the corresponding tumor tissue (D). Panels (E) to (H) show sequence analyses of the cell lines and tumor tissues given in (A) to (D). Fluorescent capillary electrophoresis patterns for the N-RAS exon 2 sequence with a CAA>CGA mutation at codon 61 in the cell line Ma-Mel-05 (I) and the corresponding tumor tissue (J). Migration patterns for the N-RAS exon 2 fragments with wild-type sequences in the cell line Ma-Mel-59 (K) and the corresponding tumor tissue (L). Panels (M) to (P) show the confirmation of the mutations in the cell lines and tissues shown in (I) to (L) by sequence analysis.</p

Kaplan-Meier survival estimation for the whole patient population by mutational status.

<p>Curves showing the overall survival of 109 metastatic melanoma patients starting from the time point of tumor biopsy. Survival probabilities were compared by the mutational status of B-RAF in tumor tissue biopsies (n = 97) (A) and biopsy-derived tumor cell lines (n = 105) (D), as well as N-RAS in tumor tissue biopsies (n = 97) (B) and biopsy-derived tumor cell lines (n = 105) (E). (C) and (F) differentiate patients harbouring B-RAF mutations (n = 52, tissues; n = 52, cell lines), patients harbouring N-RAS mutations (n = 21, tissues; n = 25; cell lines), and patients without mutations in both genes (n = 24, tissues; n = 27, cell lines). Statistical differences between groups were calculated using the log-rank test. Vertical bars indicate censored observations.</p

Schematic presentation of the study flow.

<p>Schematic presentation of the study flow.</p

Patient characteristics.

<p>Patients were enrolled in accordance with the following eligibility criteria: histologically confirmed melanoma of the skin, mucosa, or unknown primary; stage III or IV disease; and at least one metastatic lesion accessible for a bioptic procedure. AJCC, American Joint Committee on Cancer; NM, nodular melanoma; SSM, superficial spreading melanoma; ALM, acrolentiginous melanoma; LMM, lentigo maligna melanoma; occult, melanoma of unknown primary; n.a., not available.</p

Overview on B-RAF and N-RAS mutation status.

<p>Tumor tissue biopsies and biopsy-derived cell lines from 109 metastatic melanoma patients were analysed for B-RAF and N-RAS mutations. For details see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000236#pone-0000236-g001" target="_blank"><i>Figure 1</i></a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000236#pone-0000236-t002" target="_blank"><i>Table 2</i></a>. *This cell line additionally carries the N-RAS Q61K mutation.</p

Detailed patient characteristics and tumor mutation status.

<p>DNA was extracted from 97 tissue biopsies and 105 biopsy-derived cell lines from 109 metastatic melanoma patients, and screened for mutations in exons 11 and 15 of the B-RAF gene and exons 1 and 2 of the N-RAS gene. AJCC, American Joint Committee on Cancer; NM, nodular melanoma; SSM, superficial spreading melanoma; ALM, acrolentiginous melanoma; LMM, lentigo maligna melanoma; occult, melanoma of unknown primary; C/SQ, cutaneous or subcutaneous metastasis; LN, lymph node metastasis; wt, wildtype; n.a., not available; n.d., not done.</p

Use of an integrated strip-free blood glucose monitoring system increases frequency of self-monitoring and improves glycemic control: Results from the ExAct study

Aims: We investigated the impact of using an integrated, strip-free system compared to the use of single-strip systems on testing frequency and glycemic control in individuals with insulin-treated diabetes. Methods: This multinational, comparative, cluster-randomized, observational study included 311 patients with type 1 and insulin-treated type 2 diabetes who were performing SMBG at suboptimal frequencies. Sites were cluster-randomized to “integrated strip-free” system (EXP group) or any “single-strip” system (CNL group). Testing frequency and HbA1c were measured at baseline, 12 weeks and 24 weeks. Results: At week 24, the EXP group showed an increase in SMBG frequency from baseline of 4.17 tests/week (95% CI 2.76, 5.58) compared with an increase of 0.53 tests/week (95% CI −0.73, 1.79) among CNL patients, resulting in a between-group difference of 3.63 tests/week (p < 0.0002). Mixed-effects models for repeated measurements (MMRM) controlling for baseline frequency of testing, country and clinical site confirmed a higher SMBG testing frequency in the EXP group compared to the CNL group, with a between-group difference of 2.70 tests/week (p < 0.01). Univariate analysis showed greater HbA1c reductions in the EXP group than CNL group: −0.44% (95% CI −0.59, −0.29) vs. −0.13% (95% CI −0.27, 0.01), respectively, p < 0.0002. MMRM analyses confirmed these HbA1c reductions. A greater percentage of EXP than CNL patients achieved HbA1c reductions of ≥0.5%: 45.1% vs. 29.1%, respectively, p < 0.01. Conclusions: The use of an integrated, strip-free SMBG system improved testing adherence and was associated with improvements in glycemic control