TP53 status predicts long-term survival in locally advanced breast cancer after primary chemotherapy

Germline TP53 pathogenic variants and breast cancer: A narrative review

Approximately 10% of breast cancers are associated with the inheritance of a pathogenic variant (PV) in one of the breast cancer susceptibility genes. Multiple breast cancer predisposing genes, including TP53, are responsible for the increased breast cancer risk. Tumor protein-53 (TP53) germline PVs are associated with Li-Fraumeni syndrome, a rare autosomal dominant inherited cancer predisposition syndrome associated with early-onset pediatric and multiple primary cancers such as soft tissue and bone sarcomas, breast cancer, brain tumors, adrenocortical carcinomas and leukemias. Women harboring a TP53 PV carry a lifetime risk of developing breast cancer of 80-90%. The aim of the present narrative review is to provide a comprehensive overview of the criteria for offering TP53 testing, prevalence of TP53 carriers among patients with breast cancer, and what is known about its prognostic and therapeutic implications. A summary of the current indications of secondary cancer surveillance and survivorship issues are also provided. Finally, the spectrum of TP53 alteration and testing is discussed. The optimal strategies for the treatment of breast cancer in patients harboring TP53 PVs poses certain challenges. Current guidelines favor the option of performing mastectomy rather than lumpectomy to avoid adjuvant radiotherapy and subsequent risk of radiation-induced second primary malignancies, with careful consideration of radiation when indicated post-mastectomy. Some studies suggest that patients with breast cancer and germline TP53 PV might have worse survival outcomes compared to patients with breast cancer and wild type germline TP53 status. Annual breast magnetic resonance imaging (MRI) and whole-body MRI are recommended as secondary prevention.

Significant impact of circulating tumour DNA mutations on survival in metastatic breast cancer patients

Mutational analysis of circulating tumour (ct) DNA holds promise as an effective tool to predict the course of metastatic breast cancer (MBC). In the present study we used targeted next generation sequencing of ctDNA to evaluate the impact of cancer driven mutations on the prognosis of MBC. The study included 59 oestrogen receptor-positive (ER+), HER2-negative MBC patients. Sequencing analysis was performed in ESR1, PIK3CA, ERBB2, PTEN, TP53, KRAS, HRAS, NRAS, and AR. At baseline, patients started receiving either chemotherapy (34%; n = 20) or cyclin-dependent kinase 4/6 inhibitor therapy in combination with endocrine therapy (CDK4/6i+ET; 66%; n = 39). Overall, 64.4% (n = 38) of the patients carried at least one pathogenic or likely-pathogenic mutation. Number of ctDNA mutations was significantly linked with worse progression free survival (PFS; p = 0.003) and overall survival (OS; p = 0.007). Furthermore, ctDNA load, defined by the number of mutant ctDNA molecules per mL plasma, significantly correlated with PFS (p < 0.001) and OS (p = 0.001). Furthermore, mutational status of ESR1 and TP53 significantly predicted PFS (p = 0.024 and p = 0.035, respectively) and OS (p < 0.001 and p = 0.035, respectively). These results emphasizes the clinical value of ctDNA mutational analysis in the management of advanced breast cancer.

TP53 Mutations and Outcomes in Breast Cancer: Reading beyond the Headlines

TP53 is the most frequently mutated gene in breast cancer, but its role in survival is confounded by different studies concluding that TP53 mutations are associated with negative, neutral, or positive outcomes. Closer examination showed that many studies were limited by factors such as imprecise methods to detect TP53 mutations and small cohorts that combined patients treated with drugs having very different mechanisms of action. When only studies of patients receiving the same treatment(s) were compared, they tended to agree. These analyses reveal a role for TP53 in response to different treatments as complex as its different biological activities. We discuss studies that have assessed the role of TP53 mutations in breast cancer treatment and limitations in interpreting reported results.

Mutant p53 Gain-of-Function: Role in Cancer Development, Progression, and Therapeutic Approaches

Frequent p53 mutations (mutp53) not only abolish tumor suppressor capacities but confer various gain-of-function (GOF) activities that impacts molecules and pathways now regarded as central for tumor development and progression. Although the complete impact of GOF is still far from being fully understood, the effects on proliferation, migration, metabolic reprogramming, and immune evasion, among others, certainly constitute major driving forces for human tumors harboring them. In this review we discuss major molecular mechanisms driven by mutp53 GOF. We present novel mechanistic insights on their effects over key functional molecules and processes involved in cancer. We analyze new mechanistic insights impacting processes such as immune system evasion, metabolic reprogramming, and stemness. In particular, the increased lipogenic activity through the mevalonate pathway (MVA) and the alteration of metabolic homeostasis due to interactions between mutp53 and AMP-activated protein kinase (AMPK) and Sterol regulatory element-binding protein 1 (SREBP1) that impact anabolic pathways and favor metabolic reprograming. We address, in detail, the impact of mutp53 over metabolic reprogramming and the Warburg effect observed in cancer cells as a consequence, not only of loss-of-function of p53, but rather as an effect of GOF that is crucial for the imbalance between glycolysis and oxidative phosphorylation. Additionally, transcriptional activation of new targets, resulting from interaction of mutp53 with NF-kB, HIF-1α, or SREBP1, are presented and discussed. Finally, we discuss perspectives for targeting molecules and pathways involved in chemo-resistance of tumor cells resulting from mutp53 GOF. We discuss and stress the fact that the status of p53 currently constitutes one of the most relevant criteria to understand the role of autophagy as a survival mechanism in cancer, and propose new therapeutic approaches that could promote the reduction of GOF effects exercised by mutp53 in cancer.

Association of p53 expression with poor prognosis in patients with triple-negative breast invasive ductal carcinoma

TP53 gene is mutated in approximately 80% of triple-negative breast cancer (TNBC). However, the prognostic significance of immunohistochemical (IHC)-detected p53 protein expression remains controversial in TNBC. In this study, we retrospectively analyzed the association between IHC-detected p53 expression and the prognosis in a cohort of 278 patients with stage I-III triple-negative breast invasive ductal carcinoma (IDC), who received surgery at the department of breast surgery in the Fourth Hospital of Hebei Medical University from 2010-01 to 2012-12. We found a positive expression ratio of IHC-detected p53 in triple-negative breast IDC of 58.6% (163/278). Furthermore, levels of expression were significantly associated with vessel tumor emboli and higher histologic grade (P = .038, P = .043, respectively), with the highest expression level observed in G3 breast cancer (64.7%). Additionally, Kaplan-Meier analysis showed that p53 expression indicated worse overall survival (OS) in the whole cohort (79.6% vs 89.6%, Log-rank test P = .025) as well as in stratified prognostic stage II patients (90.8% vs 100%, Log-rank test P = .027). The mortality risk of p53 expression patients was 2.22 times higher than that of p53 negative patients (HR: 2.222; 95%CI: 1.147-4.308). In addition, p53 expression was also associated with poor disease-free survival (DFS) (76.7% vs 86.8%, P = .020). Cox proportional hazard ratio model showed p53 expression was an independent risk factor for OS (P = .018) and DFS (P = .018) after controlling for tumor size, lymph node status, and vessel tumor emboli. Altogether, our data showed that IHC-detected p53 expression is a promising prognostic candidate for poor survival in triple-negative breast IDC patients. However, more studies are needed to determine if p53 may be applied to clinical practice as a biomarker and/or novel therapeutic target for TNBC.

An IRAK1-PIN1 signalling axis drives intrinsic tumour resistance to radiation therapy

Drug-based strategies to overcome tumour resistance to radiotherapy (R-RT) remain limited by the single-agent toxicity of traditional radiosensitizers (e.g., platinums) and a lack of targeted alternatives. In a screen for compounds that restore radiosensitivity in p53 mutant zebrafish while tolerated in non-irradiated wild-type animals, we identified the benzimidazole anthelmintic, oxfendazole. Surprisingly, oxfendazole acts via inhibition of IRAK1, a kinase otherwise involved in Interleukin-1 and Toll-like receptor (IL-1R/TLR) immune responses. IRAK1 drives R-RT in a pathway involving IRAK4 and TRAF6 but not the IL-1R/TLR—IRAK adaptor MyD88. Rather than stimulating NF-κB, radiation-activated IRAK1 acts to prevent apoptosis mediated by the PIDDosome complex (PIDD/RAIDD/caspase-2). Countering this pathway with IRAK1 inhibitors suppresses R-RT in tumour models derived from cancers in which TP53 mutations predict R-RT. Lastly, IRAK1 inhibitors synergize with inhibitors of PIN1, a prolyl isomerase essential for IRAK1 activation in response to pathogens and, as shown here, ionizing radiation. These data identify an IRAK1 radiation-response pathway as a rational chemo-RT target.

Identifying Circulating Tumor DNA Mutation Profiles in Metastatic Breast Cancer Patients with Multiline Resistance

Purpose

In cancer patients, tumor gene mutations contribute to drug resistance and treatment failure. In patients with metastatic breast cancer (MBC), these mutations increase after multiline treatment, thereby decreasing treatment efficiency. The aim of this study was to evaluate gene mutation patterns in MBC patients to predict drug resistance and disease progression.

Method

A total of 68 MBC patients who had received multiline treatment were recruited. Circulating tumor DNA (ctDNA) mutations were evaluated and compared among hormone receptor (HR)/human epidermal growth factor receptor 2 (HER2) subgroups.

Results

The baseline gene mutation pattern (at the time of recruitment) varied among HR/HER2 subtypes. BRCA1 and MED12 were frequently mutated in triple negative breast cancer (TNBC) patients, PIK3CA and FAT1 mutations were frequent in HR+ patients, and PIK3CA and ERBB2 mutations were frequent in HER2+ patients. Gene mutation patterns also varied in patients who progressed within either 3 months or 3–6 months of chemotherapy treatment. For example, in HR+ patients who progressed within 3 months of treatment, the frequency of TERT mutations significantly increased. Other related mutations included FAT1 and NOTCH4. In HR+ patients who progressed within 3–6 months, PIK3CA, TP53, MLL3, ERBB2, NOTCH2, and ERS1 were the candidate mutations. This suggests that different mechanisms underlie disease progression at different times after treatment initiation. In the COX model, the ctDNA TP53 + PIK3CA gene mutation pattern successfully predicted progression within 6 months.

Conclusion

ctDNA gene mutation profiles differed among HR/HER2 subtypes of MBC patients. By identifying mutations associated with treatment resistance, we hope to improve therapy selection for MBC patients who received multiline treatment.

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Doctors felt difficult to design effective regimen for MBC patients after multi-line treatment.

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ctDNA testing provide potential treatment targets and reflect treatment response of tumors.

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ctDNA gene mutation pattern varies among four HR/HER2 subgroups.

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The gene mutation patterns also varied between resistant patients and sensitive patients.

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In COX model, ctDNA gene mutation pattern could successfully predict progression within 6 months.

In this study, we clarified the baseline ctDNA mutation pattern for metastatic breast cancer patients. We also selected out treatment-resistance related mutations by ctDNA testing. Here, we showed that PIK3CA were significantly related to HR+.

Moreover, in this study, we also showed a plenty of other rare mutations, including DDR2, CDK12, etc. For different HR/HER2 subtypes, MED12 was frequent in TNBC samples, FAT1 was frequent in HR+ samples, and DDR2 was frequent in HER2+ samples. These findings need further intensive investigations in larger samples.

Survival Outcomes by TP53 Mutation Status in Metastatic Breast Cancer

Purpose

We sought to determine the significant genomic alterations in patients with metastatic breast cancer (MBC), and survival outcomes in common genotypes.

Patients and Methods

High-depth next generation sequencing was performed for 202 genes in tumor and normal DNA from 257 patients with MBC, including 165 patients with ER/PR+ HER2- (hormone receptor positive, HR+ positive), 32 patients with HER2+ and 60 patients with triple negative (ER/PR/HER2-) cancer. Kaplan Meier survival analysis was performed in our discovery set, in breast cancer patients analyzed in The Cancer Genome Atlas, and in a separate cohort of 98 patients with MBC who underwent clinical genomic testing.

Results

Significantly mutated genes (SMGs) varied by histology and tumor subtype, but TP53 was a SMG in all three subtypes. The most SMGs in HR+ patients included PIK3CA (32%), TP53 (29%), GATA3 (15%), CDH1 (8%), MAP3K1 (8%), PTEN (5%), TGFBR2 (4%), AKT1 (4%), and MAP2K4 (4%). TP53 mutations were associated with shorter recurrence-free survival (P=0.004), progression-free survival (P=0.00057) and overall survival (P=0.003). Further, TP53 status was prognostic among HR+ patients with PIK3CA mutations. TP53 mutations were also associated with poorer overall survival in the 442 HR+ breast cancer patients in the TCGA (P=0.042) and in an independent set of 96 HR+ MBC who underwent clinical sequencing (P=0.0004).

Conclusions

SMGs differ by tumor subtype but TP53 is significantly mutated in all three breast cancer subtypes. TP53 mutations are associated with poor prognosis in HR+ breast cancer. TP53 mutations should be considered in the design and interpretation of precision oncology trials.

Prior systemic treatment increased the incidence of somatic mutations in metastatic breast cancer

BACKGROUND

Understanding the biology of breast cancer is important for guiding treatment strategies and revealing resistance mechanisms. Our objectives were to investigate the relationship between previous systemic therapy exposure and mutational spectrum in metastatic breast cancer and to identify clinicopathological factors associated with identified frequent somatic mutations.

METHODS

Archival tissues of patients with metastatic breast cancer were subjected to hotspot molecular testing by next-generation sequencing. The variables that significantly differed (P < 0.05) in univariate analysis were selected to fit multivariate models. Logistic models were fit to estimate the association between mutation status and clinical variables of interest. Five-fold cross-validation was performed to estimate the prediction error of each model.

RESULTS

A total of 922 patients were included in the analysis. In multivariate analysis, previous systemic treatment before molecular testing (N = 186) was associated with a significantly higher rate of TP53 and PIK3CA mutations compared with the lack of systemic treatment (P < 0.001 for both).

CONCLUSION

Systemic treatment exposure is an independent risk factor for high rates of TP53 and PIK3CA mutation, which suggests the importance of testing samples after systemic therapy to accurately assess mutations. It is worth testing the gene profile when tumours become resistant to systemic treatments.

High PTEN gene expression is a negative prognostic marker in human primary breast cancers with preserved p53 function

Purpose

PTEN is an important tumor suppressor in breast cancer. Here, we examined the prognostic and predictive value of PTEN and PTEN pseudogene (PTENP1) gene expression in patients with locally advanced breast cancer given neoadjuvant chemotherapy.

Methods

The association between pretreatment PTEN and PTENP1 gene expression, response to neoadjuvant chemotherapy, and recurrence-free and disease-specific survival was assessed in 364 patients with locally advanced breast cancer given doxorubicin, 5-fluorouracil/mitomycin, or epirubicin versus paclitaxel in three phase II prospective studies. Further, protein expression of PTEN or phosphorylated Akt, S6 kinase, and 4EBP1 was assessed in a subgroup of 187 tumors.

Results

Neither PTEN nor PTENP1 gene expression level predicted response to any of the chemotherapy regimens tested (n = 317). Among patients without distant metastases (n = 282), a high pretreatment PTEN mRNA level was associated with inferior relapse-free (RFS; p = 0.001) and disease-specific survival (DSS; p = 0.003). Notably, this association was limited to patients harboring TP53 wild-type tumors (RFS; p = 0.003, DSS; p = 0.009). PTEN mRNA correlated significantly with PTENP1 mRNA levels (r_s = 0.456, p < 0.0001) and PTEN protein staining (r_s = 0.163, p = 0.036). However, no correlation between PTEN, phosphorylated Akt, S6 kinase or 4EBP1 protein staining, and survival was recorded. Similarly, no correlation between PTENP1 gene expression and survival outcome was observed.

Conclusion

High intratumoral PTEN gene expression was associated with poor prognosis in patients with locally advanced breast cancers harboring wild-type TP53.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4160-5) contains supplementary material, which is available to authorized users.

Heterogeneous perivascular cell coverage affects breast cancer metastasis and response to chemotherapy

Angiogenesis and co-optive vascular remodeling are prerequisites of solid tumor growth. Vascular heterogeneity, notably perivascular composition, may play a critical role in determining the rate of cancer progression. The contribution of vascular pericyte heterogeneity to cancer progression and therapy response is unknown. Here, we show that angiopoietin-2 (Ang2) orchestrates pericyte heterogeneity in breast cancer with an effect on metastatic disease and response to chemotherapy. Using multispectral imaging of human breast tumor specimens, we report that perivascular composition, as defined by the ratio of PDGFRβ^- and desmin⁺ pericytes, provides information about the response to epirubicin but not paclitaxel. Using 17 distinct patient-derived breast cancer xenografts, we demonstrate a cancer cell-derived influence on stromal Ang2 production and a cancer cell-defined control over tumor vasculature and perivascular heterogeneity. The aggressive features of tumors and their distinct response to therapies may thus emerge by the cancer cell-defined engagement of distinct and heterogeneous angiogenic programs.

Association between Mutation and Expression of TP53 as a Potential Prognostic Marker of Triple-Negative Breast Cancer

Purpose

TP53, the most frequently mutated gene in breast cancer, is more frequently altered in HER2-enriched and basal-like breast cancer. However, no studies have clarified the role of TP53 status as a prognostic and predictive marker of triple-negative breast cancer (TNBC).

Materials and Methods

We performed p53 immunohistochemistry (IHC), nCounter mRNA expression assay, and DNA sequencing to determine the relationship between TP53 alteration and clinical outcomes of TNBC patients.

Results

Seventy-seven of 174 TNBC patients were found to harbor a TP53 mutation. Patients with missense mutations showed high protein expression in contrast to patients with deletion mutations (positivity of IHC: wild type vs. missense vs. deletion mutation, 53.6% vs. 89.8% vs. 25.0%, respectively; p < 0.001). TP53 mRNA expression was influenced by mutation status (mRNA expression [median]: wild type vs. missense vs. deletion mutation, 207.36± 132.73 vs. 339.61±143.21 vs. 99.53±99.57, respectively; p < 0.001). According to survival analysis, neither class of mutation nor protein or mRNA expression status had any impact on patient prognosis. In subgroup analysis, low mRNA expression was associated with poor prognosis in patients with a TP53 missense mutation (5-year distant recurrence-free survival [5Y DRFS]: low vs. high, 50.0% vs. 87.8%; p=0.009), while high mRNA expression with a TP53 deletion mutation indicated poor prognosis (5Y DRFS: low vs. high, 91.7% vs. 75.0%; p=0.316).

Conclusion

Association between TP53 mutation and expression indicates a potential prognostic marker of TNBC; hence both DNA sequencing and mRNA expression analysis may be required to predict the prognosis of TNBC patients.

TP53 mutations are associated with higher rates of pathologic complete response to anthracycline/cyclophosphamide-based neoadjuvant chemotherapy in operable primary breast cancer

The role of TP53 mutations in predicting response to neoadjuvant chemotherapy in breast cancer remains controversial. The aims of this study were to investigate whether TP53 mutations were associated with response and survival in breast cancer patients who received neoadjuvant chemotherapy. Therefore, we identified TP53 mutations in the core-needle biopsy tumor samples obtained before the neoadjuvant chemotherapy from 351 operable primary breast cancer patients who either received anthracycline/cyclophosphamide-based (n = 252) or paclitaxel (n = 99) neoadjuvant chemotherapy. We found that 41.0% (144 of 351) of patients harbored TP53 mutations, and 14.8% of patients achieved a pCR (pathologic complete response) after neoadjuvant chemotherapy. Among patients treated with anthracycline/cyclophosphamide (n = 252), patients with TP53 mutations had a significantly higher pCR rate than those with wild-type (28.6 vs.7.1%; p < 0.001), and TP53 mutation was an independent favorable predictor of pCR [odds ratio (OR) = 3.41; 95% confidence interval (CI) 1.50-7.77; p = 0.003] in this group; moreover, patients with TP53 mutation had a better distant recurrence-free survival (DRFS) than those with wild-type [unadjusted hazard ratio (HR) = 0.43; 95% CI 0.20-0.94; p = 0.030] in this group. Among patients treated with paclitaxel (n = 99), no significant difference in pCR rates was observed between patients with or without TP53 mutations (15.2 vs. 11.3%; p = 0.57). Our results suggested that patients with TP53 mutations are more likely to respond to anthracycline/ cyclophosphamide-based neoadjuvant chemotherapy and have a favorable survival.