Prognostic value of KRAS and BRAF mutations in curatively resected colorectal cancer

AIM: To investigate the prognostic role of KRAS and BRAF mutations after adjustment for microsatellite instability(MSI) status in Japanese colorectal cancer(CRC) population.METHODS: We assessed KRAS and BRAF mutations and MSI status in 813 Japanese patients with curatively resected, stage Ⅰ-Ⅲ CRC and examined associations of these mutations with disease-free survival(DFS) and overall survival(OS) using uni- and multivariate Cox proportional hazards models.RESULTS: KRAS and BRAF mutations were detected in 312(38%) of 812 and 40(5%) of 811 tumors, respectively. KRAS mutations occurred more frequently in females than in males(P = 0.02), while the presence of BRAF mutations was significantly associated with the female gender(P = 0.006), proximal tumor location(P 0.001), mucinous or poorly differentiated histology(P 0.001), and MSI-high tumors(P 0.001). After adjusting for relevant variables, including MSI status, KRAS mutations were associated with poorer DFS(HR = 1.35; 95%CI: 1.03-1.75) and OS(HR = 1.46; 95%CI: 1.09-1.97). BRAF mutations were poor prognostic factors for DFS(HR = 2.20; 95%CI: 1.19-4.06) and OS(HR = 2.30; 95%CI: 1.15-4.71). Neither the BRAF by MSI interaction test nor the KRAS by MSI interaction test yielded statistically significant results for DFS and OS.CONCLUSION: KRAS and BRAF mutations are associated with inferior survival, independent of MSI status, inJapanese patients with curatively resected CRC.     

Prognostic significance of p53 and bcl-2 abnormalities in operable nonsmall cell lung cancer.

The association of p53 abnormalities and bcl-2 protein expression with clinical data and prognosis in 102 patients with resected nonsmall cell lung cancer (NSCLC) was investigated. Deoxyribonucleic acid analysis of exons 5-8 of the p53 gene showed mutations (p53-M) in 47% of resected NSCLC, serum p53 antibodies (p53-Abs) were detected in 25%, p53 protein overexpression (p53-PE) in 54%, and bcl-2 protein overexpression (bcl-2-PE) in 48%. A statistically significant association was found between p53-PE, serum p53-Abs and the presence of a p53 gene alteration. No significant associations were found between results of the p53-M, p53-Abs, bcl-2-PE tests and clinicopathological parameters. In the case of the p53-PE test there were significantly fewer positive results for adenocarcinoma than for squamous cell carcinoma and large cell carcinoma. Survival analysis showed that both p53 abnormalities and negative staining for bcl-2, when analysed separately, were associated with poor overall survival. In a multivariate analysis, only the positive result of the p53-M test remained an independent, statistically significant, unfavourable prognostic factor for survival. When the p53 mutation test was removed from the model, positive results of the p53-PE test and the p53-Abs test became statistically significant, unfavourable prognostic factors. To conclude, among p53 and bcl-2 abnormalities, only p53 gene mutations seem to have a strong and independent effect on prognosis. When deoxyribonucleic acid sequence information is not available, p53 protein expression and the presence of p53 antibodies in serum may be used to obtain important prognostic information.     

KRAS codon 12 mutations in Australian non-small cell lung cancer

Background: In certain non-small cell lung cancer (NSCLC) populations, codon 12 mutations of the KRAS oncogene comprising mostly G-T transversions have diagnostic and prognostic value. However, it is not known if these findings are applicable to all populations of lung cancer patients. Aims: To examine for KRAS codon 12 mutations in Australian NSCLC patients. Methods: Tumour samples and corresponding normal lung tissue from 108 Australian patients with NSCLC undergoing curative resection were studied for mutations of KRAS codon 12 using a sensitive PCR assay. Mutations were confirmed by DNA sequencing and correlated with histological subtype, tumour stage, the presence of nodal metastases and survival. Results: Eleven KRAS codon 12 mutations were detected in 108 NSCLCs, with most (8/11) occurring in the adenocarcinoma subtype (17% prevalence), but were not associated with adverse outcome or clinico-pathological features. G-T transversions were surprisingly infrequent (37% of adenocarcinoma mutations). Conclusions: These data add to the evidence suggesting geographical differences in the spectrum and significance of KRAS codon 12 mutational genotypes in NSCLC. While these may be due to genetic variation and/or differences in carcinogen exposure, there is a need for larger population based studies before this potentially important biomarker can be recommended universally for optimising lung cancer management. (Aust NZ J Med 1998; 28: 184–189.)     

Impact of KRAS and TP53 mutations on survival in patients with left- and right-sided Dukes' C colon cancer

OBJECTIVE: It has been suggested that KRAS and TP53 mutated tumors might influence the phenotypic behavior of left- and right-sided colon tumors. We investigated the incidence of these mutations in left- and right-sided colon tumors and their possible influence on survival in a homogeneous group of patients with Dukes' C colon cancers. METHODS: The primary tumors of 55 patients with a sporadic Dukes' C colon cancer, all treated with adjuvant chemotherapy were analyzed for the presence of KRAS and TP53 mutations. Mutation detection of the KRAS and TP53 genes was performed on paraffin-embedded tumor material, using denaturating gradient gel electrophoresis. The 5-yr survival rates of KRAS and TP53 mutated tumors were analyzed regarding right-sided tumors (defined as tumors up to the splenic flexure) and left-sided tumors (defined as tumors from the splenic flexure to the rectosigmoid peritoneal reflection). RESULTS: KRAS mutations occurred more frequently in the right colon compared to the left colon (R = 38% (10/26); L = 10% (3/29); chi2 test: p = 0.014). KRAS mutations did not influence survival in patients with right-sided colon tumors. Patients with KRAS mutation-negative tumors in the right colon, however, had a significantly worse survival than patients with left-sided KRAS mutation-negative tumors (5-yr survival; R: 34% vs L: 65%, log-rank test: p = 0.007). TP53 mutations of a possible causative nature were found in 24 tumors (44%). Neither the incidence (R = 42% (11/26); L = 45% (13/29)) nor the survival of TP53 mutated tumors differed significantly between left- and right-sided tumors. Furthermore, survival of patients with TP53 mutation-negative tumors did not differ significantly between left- and right-sided tumors. CONCLUSIONS: There seems to be no difference in survival rate between patients with KRAS mutated and KRAS negative Dukes' C colon tumors; however, KRAS mutations are more frequently found in the right colon compared to the left colon. TP53 mutations do not have predominance for either side of the colon, and there are no differences in survival in patients with left-sided versus right-sided tumors. Patients with KRAS-nonmutated tumors in the right colon did have a worse survival compared to those with such tumors in the left colon. This suggests that other genetic factors may play a role in tumor genesis in this subgroup of patients.     

EGFR and KRAS mutational profiling in fresh non-small cell lung cancer (NSCLC) cells

Purpose

Knowledge of tumor mutational status has become a priority for effective NSCLC-tailored treatment. NSCLC diagnosis is more often reached through biopsy; thus, there is a clear need to implement for routine tumor molecular profiling on small cytological samples. This work aims to screen and compare the EGFR and KRAS mutational prevalence in fresh tumor cells and in corresponding routinely processed samples derived from trans-thoracic fine-needle aspiration. The latter currently represents the most appropriate diagnostic procedure in case of peripheral lesions, such as adenocarcinomas, which account for almost 40 % of all NSCLCs and for the highest EGFR mutational rates.

Methods

Two hundred and forty-four patients carrying peripheral lung masses underwent CT-guided aspiration. The obtained material was split, and a part was addressed to conventional histopathological analysis while the remaining one was stored at ?20 °C. In case of confirmation of adenocarcinoma, tumor genomic DNA was extracted from both fresh and fixed material, and EGFR and KRAS sequencing was performed.

Results

We identified 136 adenocarcinomas; from 134, we could recover enough material for the study. A full match was demonstrated between EGFR/KRAS mutational prevalences through the two approaches tested. We found EGFR mutations in 13 patients (9.7 %); 7 were females and 11 never or former smokers. KRAS mutations occurred in 20 (14.9 %) patients. EGFR and KRAS mutations were mutually exclusive.

Conclusions

Mutational screening on fresh cancer cells is an achievable, safe and cost-effective procedure which might allow routinely tumor molecular profiling as powerful integration of conventional histopathological analysis.     

Prognostic role of epidermal growth factor receptor in stage III nonsmall cell lung cancer.

New biological factors have not been extensively studied in stage III nonsmall cell lung cancer (NSCLC). The aim of the present retrospective study was to determine the role of epidermal growth factor receptor (EGF-R) as a prognostic factor in stage III NSCLC, in addition to the stage and other known clinical factors. Clinical characteristics were retrieved from the patients' charts. Membrane immunostaining for EGF-R was evaluated by three independent observers. The Cox multivariate model, including all variables with a p-value of <0.2 in univariate analysis, was used to assess the impact of clinical and biological factors on patients survival. Between January 1987 and July 2002, 99 assessable stage III NSCLC patients were included in the study. A total of 23 patients were positive for EGF-R (squamous 39.6% versus nonsquamous 7.8%). In multivariate analysis, only three factors were statistically significantly associated with survival: performance status, surgery and creatinine. In conclusion, good performance status, surgical resection and creatinine were found to be independent favourable prognostic factors for survival in a retrospective analysis of stage III nonsmall cell lung cancer, while epidermal growth factor receptor was not even in the univariate analysis.     

Prognostic value of lactate dehydrogenase in non-small cell lung cancer patients with brain metastases: a retrospective cohort study

BackgroundAt present, although there are some known molecular markers for the prognosis of non-small cell lung cancer (NSCLC) brain metastases, but there are still shortcomings in sensitivity and specificity. Lactate dehydrogenase (LDH) is one of the key enzymes involved in malignancy vital glycolytic pathway. Elevated serum LDH levels are reported significantly associated with a poor prognosis in various malignancies. However, there is currently no consensus regarding the prognostic value of LDH in NSCLC patients with brain metastases.MethodsWe retrospectively analyzed 224 patients diagnosed with lung cancer brain metastases between January 2006 and June 2020 after excluding patients meeting combined with other malignancies and inaccurate clinical information. The LDH cutoff values were obtained using a restricted cubic spline (RCS) model, and the patients were divided into two groups according to the optimal cut-off value (180 U/L). 107 patients with LDH ≤180 (47.77%) and 117 patients with LDH >180 (52.23%) were identified. Univariate and multivariate logistic regression analyses were performed to identify the risk factors. The overall survival (OS) time was defined as the time from the first diagnosis of brain metastases to the last follow-up or death. Of the included patients, 147 survived and 77 died. The Kaplan-Meier method was used to illustrate the OS difference between the two groups. Finally, sensitivity analysis was employed to evaluate the robustness of the results.ResultsThe OS rate was significantly lower in the high LDH group versus the low LDH group (P=0.009). The median survival times of the high and low LDH groups were approximately 16 and 33 months, respectively. Multivariate analysis showed that high LDH was associated with a significantly worse OS [adjusted hazard ratio (aHR), 1.567; 95% confidence interval (CI): 1.058 to 2.32, P=0.025] with adjustment for covariables that P<0.05 in univariate analysis. Sensitivity analysis indicated that the results of this study are robust, despite potential unmeasured confounders.ConclusionsHigh level of serum LDH indicates poor prognosis for patients with NSCLC brain metastases. This finding may provide useful prognostic information for patients and clinicians to choose more aggressive treatment strategies.     

Identification of EGFR and KRAS mutations in Chinese patients with esophageal squamous cell carcinoma

The prognosis of esophageal squamous cell carcinoma (ESCC) is poor. It is urgent to improve this situation. Epidermal growth factor receptor (EGFR)‐targeted therapy possesses a promising clinical efficacy. Mutations of EGFR and V‐Ki‐ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) have been identified in esophageal carcinoma, but corresponding Chinese data are limited. So we investigated the mutation status of EGFR and KRAS in Chinese patients with ESCC, and explored their correlations with clinicopathological features. Formalin‐fixed paraffin‐embedded surgically resected tumor samples were obtained from 50 randomly selected Chinese patients with ESCC. EGFR mutations in exons 18–21 were detected by Scorpions amplification refractory mutation system technology. KRAS mutations in codons 12, 13 were detected by direct sequencing of polymerase chain reaction products. The correlations between clinicopathological features and the mutation status of EGFR and KRAS were analyzed using the Statistical Package for the Social Sciences. In the present study, EGFR mutations were found in 7 (14%) out of 50 patients, including G719X missense mutation (n= 1), in‐frame deletion (n= 2), and L858R missense mutation (n= 5). Six (12%) out of 50 patients had KRAS mutations in codon 12. Concurrent EGFR and KRAS mutations were detected in one sample. The presences of EGFR and KRAS mutations were not associated with gender, age, smoking history, cell differentiation, or cancer stage. In conclusion, the incidence of EGFR mutations in Chinese patients with ESCC was higher than that of previous reports, and the incidence of KRAS mutations was not low. EGFR and KRAS mutations were mainly located in exons 19 and 21 and codon 12, respectively. Unlike in NSCLC, concurrent EGFR and KRAS mutations existed.     

Positron emission tomography in nonsmall cell lung cancer

PURPOSE OF REVIEW: [(8)F]2-Fluoro-2-deoxy-glucose positron emission tomography is an important functional imaging technique for the diagnosis, staging and follow-up of patients with nonsmall cell lung cancer. We review recent developments with the emphasis on impact of positron emission tomography in early diagnosis, staging, restaging and prognosis of nonsmall cell lung cancer. RECENT FINDINGS: Data on the use and interpretation of positron emission tomography became available for small pulmonary nodules. We should abandon the 'magic' standardized uptake value threshold of 2.5 and rather make a visual assessment in this setting. The high negative predictive value of positron emission tomography in mediastinal staging was confirmed in a large prospective study. Tissue confirmation of all qualitative or quantitative suspicious mediastinal lymph nodes at positron emission tomography remains required. Minimally invasive techniques such as endobronchial ultrasound-guided transbronchial needle aspiration seem promising in this setting with sensitivities up to 90%. Recent data also point at integrated positron emission tomography/computed tomography as a tool for response assessment of mediastinal nodes and, more interestingly, of the primary tumor. Positron emission tomography has the potential to predict survival based on baseline positron emission tomography stage and standardized uptake value, visual [(18)F]2-fluoro-2-deoxy-glucose uptake at the time of suspected recurrence, and change in [(18)F]2-fluoro-2-deoxy-glucose uptake after neoadjuvant therapy. SUMMARY: Refinements in diagnosis and staging, as well as newer applications such as guidance of endoscopy and assessment of treatment, are described.     

非小细胞肺癌表皮生长因子受体突变的检测与分子靶向治疗

目的探讨非小细胞肺癌患者表皮生长因子受体(EGFR)基因突变率和突变类型,分析其临床特征,并观察EGFR突变与表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKIs)治疗疗效的相关性。方法收集203例非小细胞肺癌患者外科手术、淋巴结活检、经皮肺穿刺活检、气管镜活检和胸腔积液沉渣石蜡标本,应用ADx-ARMS法进行EGFR基因突变检测,分析基因的突变率及其与临床特征的关系;观察非小细胞肺癌(NSCLC)接受EGFR-TKIs治疗的非小细胞肺癌患者的疗效。应用SPSS23.0软件进行统计学分析,计数资料比较采用χ2检验,采用Kaplan-Meier法计算患者的PFS,采用Log-Rank检验分析各种因素对生存期的影响。结果 203例NSCLC患者,男性116例,女性87例,年龄为25~82岁。吸烟指数≥400支/者61例,小于400支/年和不吸烟者142例,腺癌152例,鳞癌21例,腺鳞癌14例,其他NSCLC16例。203例NSCLC患者EGFR总突变率为51.2%(104/203),包括19外显子缺失突变51例(49.0%),21外显子L858R突变44例(42.3%),19del及L858R总突变率占所有突变的96.1%,18外显子G719X点突变3例(2.9%),19del+L858R双突变3例(2.9%),1例20ins,2例T790M突变分别为1例19del+T790M和1例L858R+T790M。EGFR基因阳性突变率女性组高于男性组(66.7%vs.36.2%);非吸烟组高于吸烟组(63.4%vs.16.4%);腺癌组高于鳞癌组(53.3%vs.33.3%),P0.05。而EGFR基因突变状况与标本类型如手术、淋巴结活检、肺穿刺活检、气管镜活检和胸腔积液沉渣标本间无统计学差异,P=0.418。101例接受TKI治疗的NSCLC患者客观缓解率(ORR)为61.4%,疾病控制率(DCR)为71.3%,中位疾病无进展生存期(PFS)为10个月。其中EGFR突变阳性患者接受EGFR-TKIs治疗的ORR及DCR均要显著高于EGFR突变阴性及EGFR突变状态未明确人群(88.6%vs.16.7%vs.43.1%,P=0.000;95.5%vs.16.7%vs.56.9%,P=0.000)。EGFR突变阳性患者接受EGFR-TKIs治疗的中位PFS较EGFR突变阴性及EGFR突变状态未明确患者延长,有统计学差异(P=0.001)。进一步分析EGFR突变阳性19del组NSCLC患者ORR、DCR均高于L858R组(91.2%vs.85%,P=0.646;100%vs.90%,P=0.201);19del组NSCLC患者TKI治疗后中位PFS 14.5个月较L858R组10个月长,有统计学差异(P=0.010)。结论非小细胞肺癌患者EGFR突变高,以女性、不吸烟、腺癌为优势人群,EGFR敏感突变阳性者对EGFR-TKI疗效好,EGFR突变中19del者较L858R疗效更佳,基因检测结果可以较好地预测分子靶向药物的疗效,降低肿瘤进展的风险。     

Female sex and bronchioloalveolar pathologic subtype predict EGFR mutations in non-small cell lung cancer

STUDY OBJECTIVES: The prevalence of epidermal growth factor receptor (EGFR) mutations in gefitinib-naive lung cancer patients is higher in adenocarcinomas, in women, and in Japanese. To further investigate the prevalence of EGFR mutations in relation to ethnic and geographic factors, we evaluated EGFR mutations in a series of Taiwanese patients with primary lung adenocarcinomas who had never been treated with gefitinib. DESIGN AND METHODS: We retrospectively studied 35 primary lung adenocarcinoma samples for mutations in the tyrosine kinase domain of EGFR; exons 18, 19, and 21 were analyzed by nested polymerase chain reaction and automated sequencing. Clinicopathologic information was obtained from patient records and pathology reports. Correlation between EGFR mutations and patient characteristics, including sex, smoking history, and pathologic subtypes, were evaluated by using the chi(2) test and logistic regression analysis. RESULTS: Heterozygous EGFR mutations were detected in 17 of 35 patients (48%). Missense mutations in exon 21 (13 of 17 patients, 76%) were the most frequent mutations detected. EGFR mutations were more frequent in women (13 of 18 patients [72%]) than in men (4 of 17 patients [23%]; p = 0.004), more frequent in nonsmokers (14 of 21 patients [66%]) than in current smokers (3 of 14 patients [21%]; p = 0.009), and when any degree of bronchioloalveolar carcinoma (BAC) was present (14 of 21 patients [66%]) compared with pure adenocarcinoma (3 of 14 patients [21%]; p = 0.009). Logistic regression analysis demonstrated that female gender (odds ratio [OR], 10.913; 95% confidence interval [CI], 1.778 to 66.97; p = 0.01) and BAC, including adenocarcinomas with any bronchioloalveolar features (OR, 9.708; 95% CI, 1.464 to 64.393; p = 0.019), were significantly associated with EGFR mutations. CONCLUSIONS: In our series, female sex and bronchioloalveolar pathologic subtype predicted the presence of EGFR mutations in lung adenocarcinomas, and the high frequency of EGFR mutations supports the hypothesis that genetic backgrounds and/or environmental factors may affect the pathogenesis of certain lung cancers.     

Uncommon EGFR mutations in lung carcinoma: features and treatment outcomes in a retrospective French cohort

BackgroundThe best management for rare epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung carcinoma (NSCLC) remains uncertain. The literature indicates that response to usual treatment could differ in certain subgroups such as exon 20 insertion/duplication (E20ID), other single uncommon mutation (OSUM), and EGFR complex mutation (ECM).MethodsIn this observational, regional, multi-center, retrospective study, we gathered data on uncommon EGFR mutations in NSCLC from 2007 to 2021. We analyzed patient characteristics, prognostic factors and treatment outcomes [objective response rate (ORR), disease control rate (DCR), progression free survival (PFS) and overall survival (OS)].ResultsAmong 119 patients with an uncommon EGFR mutant, 34 harbored E20ID, 23 ECM, and 62 OSUM. There were significantly more non-smokers in E20ID. Female gender and performance status <2 were associated with a better prognosis. Among the 97 metastatic patients with available data for 1st line treatment, median estimated OS was 21 months (95% CI: 18–31 months), with better non-significant OS for ECM. Median estimated PFS was 7 months (95% CI: 4–9 months). We found significant differences in ORR, DCR and PFS favoring 1st line chemotherapy for E20ID, whereas the outcomes for OSUM and ECM were more favorable for tyrosine kinase inhibitor (TKI) (mainly 2nd and 3rd generation).ConclusionsThere were variations in treatment outcomes among subgroups in our cohort. Exon 20 insertions showed better ORR and PFS with 1st line chemotherapy compared to TKI. Conversely, other rare EGFR mutations including ECM had better ORR and PFS with TKI than chemotherapy. There was no significant difference in OS among treatment groups overall or within rare mutation subgroups.     

Structure-based classification of EGFR mutations in operable pre-invasive and invasive non-small cell lung cancer: a cross-sectional study

BackgroundIt has been reported that the structure-based approach for defining functional groups of epidermal growth factor receptor (EGFR) mutations predicts the efficacy of EGFR inhibitors better than the traditional exon-based approach in the advanced stage. However, less is known about this structure-based classification of EGFR mutations in operable early-stage lung adenocarcinoma.MethodsNon-small cell lung cancer (NSCLC) patients with pathological stage I–III or adenocarcinoma in situ (AIS) who had EGFR mutations identified in next-generation sequencing (NGS) testing were recruited. Both exon-based and structure-based groupings of EGFR mutations were compared between the AIS and stage I–III patients using Fisher’s exact test.ResultsIn total 1,012 patients including 66 AIS and 946 stage I–III patients were analyzed in the study. A total of 1185 EGFR mutations were identified in the 1,012 NSCLC patients, of whom 84.39% harbored a single EGFR mutation and 15.61% harbored complex EGFR mutations. As expected, L858R was more common than 19del in our population (39.33% vs. 35.67%). Interestingly, concurrent L858R and 19del mutations were identified in 9 patients (0.89%), and all these patients were diagnosed with multiple primary lung cancer. A higher percentage of atypical EGFR mutations was identified in the AIS cohort than in the stage I–III NSCLC cohort (33.33% vs. 21.66%, P=0.03). According to the structure-based classification of EGFR mutations, 86.07%, 7.11%, 5.04%, and 1.78% of the EGFR mutations were classified as classical-like, P-loop and α C-helix compressing (PACC), exon 20 insertions (Ex20ins), and T790M-like mutations, respectively. The composition of EGFR mutations was different between patients <65 and ≥65 years (P=0.0267) but similar between patients with AIS and stage I–III NSCLC (P=0.1436). However, a higher percentage of Ex20ins occurred in younger (<65 years) patients, nonsmoking patients, and patients with AIS (6.7% vs. 2.5%, P=0.003; 5.8% vs. 0.8%, P=0.0107; and 10.6% vs. 4.7%, P=0.0423, respectively).ConclusionsThis large cross-sectional study delineated the structure-based classification of EGFR mutations in patients with operable NSCLC. While the traditional exon-based EGFR grouping showed difference between AIS and stage I–III NSCLC cohort, no difference was identified in the structural approach. Which approach had better prediction of targeted therapy efficacy in adjuvant settings warrants further investigation.     

Prognostic and predictive biomarkers for epidermal growth factor receptor-targeted therapy in colorectal cancer: Beyond KRAS mutations

The advent of the epidermal growth factor receptor (EGFR)-targeted monoclonal antibodies (mAbs), cetuximab and panitumumab has expanded the range of treatment options for metastatic colorectal cancer (CRC). Despite these agents have paved the way to individualized therapy, our understanding why some patients respond to treatment whereas others do not remain poor. The realization that detection of positive EGFR expression by IHC does not reliably predict clinical outcome of EGFR-targeted treatment has led to an intense search for alternative predictive biomarkers. Data derived from multiple phase III trials have indicated that KRAS mutations can be considered a highly specific negative biomarker of benefit to anti-EGFR mAbs. Oncologists are now facing emerging issues in the treatment of metastatic CRC, including the identification of additional genetic determinants of primary resistance to EGFR-targeted therapy for further improving selection of patients, the explanation of rare cases of patients carrying KRAS-mutated tumours who have been reported to respond to cetuximab and panitumumab and the discovery of mechanisms of secondary resistance to EGFR-targeted therapy. Current data suggest that, together with KRAS mutations, the evaluation of EGFR gene copy number (GCN), BRAF, NRAS, PIK3CA mutations or loss of PTEN expression could also be useful for selecting patients with reduced chance to benefit from anti-EGFR mAbs.This review aims to provide an updated of the most recent data on predictive and prognostic biomarkers within the EGFR pathway, the challenges this emerging field presents and the future role of these molecular markers in CRC treatment.     

Patterns of mutations in TP53 mutated AML

TP53 mutated acute myeloid leukemia (AML) responds poorly to chemotherapy and has a short overall survival rate with a median of 5–9 months. Poor outcomes in TP53 mutated AML following chemotherapy have been observed and treatment options remain limited, although the presence of TP53 mutations alone should not be a barrier to therapy. Decitabine is emerging as an alternative treatment option for patients with TP53 mutated AML, although the agent has not been associated with deep molecular remissions and requires additional consolidation. The clinical and genomic characteristics of TP53 mutated AML are reviewed in this paper.     

TP53 mutations and relevance of expression of TP53 pathway genes in paediatric acute myeloid leukaemia

Limited data are available on the incidence and impact of TP53 alterations and TP53 pathway deregulation in paediatric acute myeloid leukaemia (AML). We analysed TP53 alterations in bone marrow samples of 229 patients with de novo paediatric AML, and detected heterozygous missense exon mutations in two patients (1%) and 17p deletions of the TP53 gene in four patients (2%). These patients more frequently had complex karyotype (50% vs. 4%, P = 0·002) or adverse cytogenetic abnormalities, including complex karyotype (67% vs. 17%, P = 0·013), compared to TP53 wild-type. Differential expression of TP53 pathway genes was associated with poor survival, indicating a role for TP53 regulators and effector genes.