Rapid selection of BRCA1-proficient tumor cells during neoadjuvant therapy for ovarian cancer in BRCA1 mutation carriers

Origin of Residual Tumor Masses in BRCA1/2-Driven Ovarian Carcinomas Treated by Neoadjuvant Chemotherapy: Selection of Preexisting BRCA1/2-Proficient Tumor Cells but Not the Gain of Second ORF-Restoring Mutation

INTRODUCTION

Tubo-ovarian carcinomas (OCs) are highly sensitive to platinum-based neoadjuvant chemotherapy (NACT) but almost never demonstrate complete pathologic response.

METHODS

We analyzed paired primary and residual tumor tissues from 30 patients with hereditary BRCA1/2-driven OCs (BRCA1: 17; BRCA2: 13), who were treated by carboplatin/paclitaxel NACT (median number of cycles: 3, range: 3-6). BRCA1/2 and TP53 genes were analyzed by the next-generation sequencing. The ratio between TP53 mutation-specific versus wild-type reads was considered to monitor the proportion of tumor and non-tumor cells in the tissue sample, and the ratio between BRCA1/2-mutated and wild-type reads was used to estimate the presence of cells with the loss or retention of heterozygosity (LOH or ROH, respectively).

RESULTS

All 30 OCs had BRCA1/2 LOH in primary tumor and carried somatic TP53 mutation. Twenty-eight OCs had sufficient tumor cell cellularity in the post-NACT tissue to evaluate the ratio between mutated and wild-type BRCA1/2 alleles. Five (18%) out of 28 informative tumor pairs showed transition from LOH to ROH during NACT presumably affecting all or the vast majority of residual tumor cells. There were no signals of the emergence of a second open reading frame-restoring BRCA1/2 mutation.

CONCLUSION

Chemonaive BRCA1/2-driven carcinomas may contain a fraction of tumor cells with preserved BRCA1/2 heterozygosity. NACT can cause a selection of pre-existing BRCA1/2-proficient tumor cells, without gaining secondary reversal BRCA1/2 mutations.

Discrimination between Complete versus Non-Complete Pathologic Response to Neoadjuvant Therapy Using Ultrasensitive Mutation Analysis: A Proof-of-Concept Study in BRCA1-Driven Breast Cancer Patients

Neoadjuvant chemotherapy (NACT) for breast cancer (BC) often results in pathologic complete response (pCR), i.e., the complete elimination of visible cancer cells. It is unclear whether the use of ultrasensitive genetic methods may still detect residual BC cells in complete responders. Breast carcinomas arising in BRCA1 mutation carriers almost always carry alterations of the TP53 gene thus providing an opportunity to address this question. The analysis of consecutive BC patients treated by NACT revealed a higher pCR rate in BRCA1-driven vs. BRCA1-wildtype BCs (13/24 (54%) vs. 29/192 (15%), p < 0.0001). Twelve pre-/post-NACT tissue pairs obtained from BRCA1 mutation carriers were available for the study. While TP53 mutation was identified in all chemonaive tumors, droplet digital PCR (ddPCR) analysis of the post-NACT tumor bed revealed the persistence of this alteration in all seven pCR-non-responders but in none of five pCR responders. Eleven patients provided to the study post-NACT tissue samples only; next-generation sequencing (NGS) analysis revealed mutated TP53 copies in all six cases without pCR but in none of five instances of pCR. In total, TP53 mutation was present in post-NACT tissues in all 13 cases without pCR, but in none of 10 patients with pCR (p < 0.000001). Therefore, the lack of visible tumor cells in the post-NACT tumor bed is indeed a reliable indicator of the complete elimination of transformed clones. Failure of ultrasensitive methods to identify patients with minimal residual disease among pCR responders suggests that the result of NACT is a categorical rather than continuous variable, where some patients are destined to be cured while others ultimately fail to experience tumor eradication.

Analysis of matched primary and recurrent BRCA1/2 mutation-associated tumors identifies recurrence-specific drivers

Recurrence is a major cause of death among BRCA1/2 mutation carriers with breast (BrCa) and ovarian cancers (OvCa). Herein we perform multi-omic sequencing on 67 paired primary and recurrent BrCa and OvCa from 27 BRCA1/2 mutation carriers to identify potential recurrence-specific drivers. PARP1 amplifications are identified in recurrences (False Discovery Rate q = 0.05), and PARP1 is significantly overexpressed across primary BrCa and recurrent BrCa and OvCa, independent of amplification status. RNA sequencing analysis finds two BRCA2 isoforms, BRCA2-201/Long and BRCA2-001/Short, respectively predicted to be sensitive and insensitive to nonsense-mediated decay. BRCA2-001/Short is expressed more frequently in recurrences and associated with reduced overall survival in breast cancer (87 vs. 121 months; Hazard Ratio = 2.5 [1.18-5.5]). Loss of heterozygosity (LOH) status is discordant in 25% of patient's primary and recurrent tumors, with switching between both LOH and lack of LOH found. Our study reveals multiple potential drivers of recurrent disease in BRCA1/2 mutation-associated cancer, improving our understanding of tumor evolution and suggesting potential biomarkers.

Does the primary treatment sequence affect post-relapse survival in recurrent epithelial ovarian cancer? A real-world multicentre retrospective study

OBJECTIVE

To explore the impact of the primary treatment sequence (primary debulking surgery, PDS, versus neoadjuvant chemotherapy and interval debulking surgery, NACT-IDS) on post-relapse survival (PRS) and recurrence characteristics of recurrent epithelial ovarian cancer (REOC).

DESIGN

Real-world retrospective study.

SETTING

Tertiary hospitals in China.

POPULATION

A total of 853 patients with REOC at International Federation of Gynaecology and Obstetrics stages IIIC-IV from September 2007 to June 2020. Overall, 377 and 476 patients received NACT-IDS and PDS, respectively.

METHODS

Propensity score-based inverse probability of treatment weighting (IPTW) was performed to balance the between-group differences.

MAIN OUTCOME MEASURES

Clinicopathological factors related to PRS.

RESULTS

The overall median PRS was 29.3 months (95% CI 27.0-31.5 months). Multivariate analysis before and after IPTW adjustment showed that NACT-IDS and residual R1/R2 disease were independent risk factors for PRS (p < 0.05). Patients with diffuse carcinomatosis and platinum-free interval (PFI) ≤ 12 months had a significantly worse PRS (p < 0.001). Logistic regression analysis revealed that NACT-IDS was an independent risk factor for diffuse carcinomatosis (OR 1.36, 95% CI 1.01-1.82, p = 0.040) and PFI ≤ 12 months (OR 1.59, 95% CI 1.08-2.35, p = 0.019). In IPTW analysis, NACT-IDS was still significantly associated with diffuse carcinomatosis (OR 1.29, 95% CI 1.05-1.58, p = 0.015) and PFI ≤ 12 months (OR 1.90, 95% CI 1.52-2.38, p < 0.001).

CONCLUSIONS

The primary treatment sequence may affect the PRS of patients with REOC by altering the recurrence pattern and PFI duration.

Cytotoxic and targeted therapy for BRCA1/2-driven cancers

Tumors arising in BRCA1/2 germline mutation carriers usually demonstrate somatic loss of the remaining BRCA1/2 allele and increased sensitivity to platinum compounds, anthracyclines, mitomycin C and poly (ADP-ribose) polymerase inhibitors (PARPi). Exposure to conventional platinum-based therapy or PARPi results in the restoration of BRCA1/2 function and development of resistance to systemic therapy, therefore, there is a need for other treatment options. Some studies suggested that the use of specific drug combinations or administration of high-dose chemotherapy may result in pronounced tumor responses. BRCA1/2-driven tumors are characterized by increased immunogenicity; promising efficacy of immune therapy has been demonstrated in a number of preclinical and clinical investigations. There are outstanding issues, which require further consideration. Platinum compounds and PARPi have very similar mode of antitumor action and are likely to render cross-resistance to each other, so their optimal position in cancer treatment schemes may be a subject of additional studies. Sporadic tumors with somatically acquired inactivation of BRCA1/2 or related genes resemble hereditary neoplasms with regard to the spectrum of drug sensitivity; the development of user-friendly BRCAness tests presents a challenge. Many therapeutic decisions are now based on the BRCA1/2 status, so the significant reduction of the turn-around time for predictive laboratory assays is of particular importance.

Mechanisms of acquired resistance of BRCA1/2-driven tumors to platinum compounds and PARP inhibitors

Molecular pathogenesis of tumors arising in BRCA1/2 germ-line mutation carriers usually includes somatic inactivation of the remaining allele of the involved gene. Consequently, BRCA1/2-driven cancers are sensitive to platinum-based therapy and poly (ADP-ribose) polymerase inhibitors (PARPi). Long-term exposure to these drugs may result in the emergence of secondary BRCA1/2 mutations, which restore the open-reading frame of the affected allele. This platinum/PARPi cross-resistance mechanism applies both for BRCA1 and BRCA2 genes and has been repeatedly validated in various laboratory models and multiple clinical studies. There are some other routes associated with the partial rescue of BRCA1/2 function or the development of BRCA1/2-independent pathways for genomic maintenance; however, their actual clinical relevance remains to be established. In addition, studies on the short-term neoadjuvant therapy for ovarian cancer revealed that even chemonaive BRCA1-driven tumors contain a small proportion of BRCA1-proficient cells. These pre-existing cells with retained BRCA1 heterozygosity rapidly repopulate the tumor mass during platinum exposure, but become outcompeted by BRCA1-deficient cells during therapy holidays. Understanding of the platinum/PARPi resistance pathways has led to the development of novel therapeutic approaches, which aim to improve the management of BRCA1/2-related cancers and are currently undergoing preclinical and clinical evaluation.

Molecular predictors of the outcome of paclitaxel plus carboplatin neoadjuvant therapy in high-grade serous ovarian cancer patients

BACKGROUND

Patients with advanced high-grade serous ovarian cancer (HGSOC) are usually treated with paclitaxel and carboplatin; however, predictive markers for this drug combination are unknown.

METHODS

Tumor samples from 71 consecutive HGSOC patients, who received neoadjuvant chemotherapy with paclitaxel and carboplatin, were subjected to molecular analysis.

RESULTS

BRCA1/2 germline mutation carriers (n = 22) had longer treatment-free interval (TFI) than non-carriers (n = 49) (9.5 months vs. 3.8 months; P = 0.007). Fifty-one HGSOCs had sufficient quality of tumor DNA for the next-generation sequencing (NGS) analysis by the SeqCap EZ CNV/LOH Backbone Design panel. All 13 tumors obtained from BRCA1/2 germline mutation carriers and 12 sporadic HGSOCs showed a high number of evenly spread chromosomal breaks, which was defined as a BRCAness phenotype; median TFI for this combined group approached 9.5 months. The remaining 26 HGSOCs had similarly high global LOH score (above 20%); however, in contrast to BRCAness tumors, LOH involved large chromosomal segments; these patients had significantly lower TFI (3.7 months; P = 0.006). All patients with CCNE1 amplification (n = 7), TP53 R175H substitution (n = 6), and RB1 mutation (n = 4) had poor response to paclitaxel plus carboplatin.

CONCLUSION

This study describes a cost-efficient method of detecting the BRCAness phenotype, which is compatible with the laboratory-scale NGS equipment. Some molecular predictors allow the identification of potential non-responders to paclitaxel plus carboplatin, who may need to be considered for other treatment options.

Neoadjuvant therapy of BRCA1-driven ovarian cancer by combination of cisplatin, mitomycin C and doxorubicin

BACKGROUND

Cisplatin, mitomycin C and anthracyclines demonstrate high activity in BRCA1-deficient tumors. This study aimed to evaluate the efficacy of the triplet combination of these drugs in BRCA1-driven high-grade serous ovarian carcinomas (HGSOCs).

METHODS

Ten HGSOC patients with germ-line BRCA1 mutation received neoadjuvant chemotherapy (NACT) consisting of mitomycin C 10 mg/m² (day 1), doxorubicin 30 mg/m² (days 1 and 8) and cisplatin 80 mg/m² (day 1), given every 4 weeks (MAP regimen). The comparator group included 16 women, who received standard NACT combination of paclitaxel 175 mg/m² and carboplatin (6 AUC), given every 3 weeks (TCbP scheme).

RESULTS

None of the patients treated by the MAP scheme demonstrated complete pathologic response in ovaries, while 4 women showed absence of tumor cells in surgically excised omental specimens. When chemotherapy response scores (CRS) were considered, poor responsiveness (CRS 1) was not observed in the MAP group, but was common for the TCbP regimen (6/16 (38 %) for ovaries and 5/16 (31 %) for omentum; p = 0.05 and 0.12, respectively). Median treatment-free interval (TFI) was not reached in women treated by the MAP, but was 9.5 months for the TCbP scheme (p = 0.1). The rate of the recurrence within 1 year after the completion of the treatment was 4/10 (40 %) for the MAP and 10/13 (77 %) for the TCbP (p = 0.1).

CONCLUSIONS

The attempt to intensify NACT by administering combination of 3 drugs did not result in high rate of complete pathologic responses. However, there was a trend towards higher efficacy of the MAP regimen versus conventional TCbP scheme with regard to CRS and clinical outcomes.

The added value of CA125 normalization before interval debulking surgery to the chemotherapy response score for the prognostication of ovarian cancer patients receiving neoadjuvant chemotherapy for advanced disease

Objective: To investigate whether CA125 normalization following neoadjuvant chemotherapy (NACT) can complement the chemotherapy response system (CRS) in the prognostication of patients with tubo-ovarian high-grade serous carcinoma (HGSC). Methods: In total, 118 HGSC patients who received NACT followed by interval debulking surgery (IDS) for FIGO stage IIIC-IV disease were included, and their clinical data were retrospectively reviewed. The primary endpoint was progression-free survival (PFS). Cox regression analysis was performed to identify predictors of PFS. Results: Following NACT, CRS3 was noted in 35 patients (29.7%), and CA125 normalization (≤ 35 U/ml) was noted in 54 patients (45.8%). Both CRS3 and CA125 normalization were identified as independent prognosticators of PFS. Combining these two factors, we stratified the 106 patients into three groups with different risks of recurrence: low-risk group (CRS3 + post-NACT CA125≤ 35 U/ml; n = 17, 14.4%), intermediate-risk group (CRS3 + post-NACT CA125 > 35 U/ml; n = 19, 16.1%) and high-risk group (CRS1-2; n= 82, 69.5%). The differences in PFS between the three groups were significant (log-rank test, P < 0.0001). In Cox regression analyses, the new stratification method was found to have an independent prognostic effect. Conclusion: Both the CRS system and the normalization of CA125 following NACT could reliably predict the risk of recurrence following primary treatment. The combination of the two factors refined the prognostic stratification of HGSC patients who were treated with NACT and IDS.

Frequency and molecular characteristics of PALB2-associated cancers in Russian patients

PALB2 is а high-penetrance gene for hereditary breast cancer (BC). Our study aimed to investigate the spectrum of PALB2 mutations in Russian cancer patients. PALB2 sequencing revealed pathogenic variants in 3/190 (1.6%) young-onset and/or familial and/or bilateral BC cases but none in 96 ovarian cancer (OC) or 172 pancreatic cancer patients. Subsequently, seven recurrent PALB2 pathogenic alleles were selected from this and previous Slavic studies and tested in an extended patient series. PALB2 pathogenic variants were detected in 5/585 (0.9%) "high-risk" BC, 10/1508 (0.7%) consecutive BC and 5/1802 (0.3%) OC cases. Haplotyping suggested that subjects with Slavic alleles c.509-510delGA (n = 10) and c.172-175delTTGT (n = 4) as well as carriers of Finnish c.1592delT mutation (n = 4) originated from a single founder each, while PALB2 p.R414X allele (n = 4) had at least two independent founders. Somatic loss of heterozygosity (LOH) was revealed in 5/10 chemonaive BCs and in 0/2 BC samples obtained after neoadjuvant therapy. Multigene sequencing identified somatic PALB2 inactivating point mutation in one out of two tumors without PALB2 LOH but in none of four BCs with PALB2 LOH. Genomic instability, as determined by NGS, was observed in four out of five tumors with biallelic PALB2 inactivation but not in the BC sample with the preserved wild-type PALB2 allele. PALB2 germ-line mutations contribute to a small fraction of cancer cases in Russia. The majority although not all PALB2-driven BCs have somatic inactivation of the remaining PALB2 allele and therefore potential sensitivity to platinum compounds and PARP inhibitors.

Germline and Somatic BRCA1/2 Gene Mutational Status and Clinical Outcomes in Epithelial Peritoneal, Ovarian, and Fallopian Tube Cancer: Over a Decade of Experience in a Single Institution in Korea

PURPOSE

This study aimed to present a single institutional experience with BRCA1/2 gene tests and the effects of pathogenic mutations in epithelial peritoneal, ovarian, and fallopian tube cancer (POFTC) on survival outcomes.

Materials and Methods

We identified patients with epithelial POFTCs who underwent BRCA1/2 gene testing by either germline or somatic methods between March 2007 and March 2020. Based on the BRCA1/2 test results, patients were divided into BRCA mutation and wild-type groups, followed by comparisons of clinicopathologic characteristics and survival outcomes after primary treatment.

RESULTS

The annual number of POFTC patients who received BRCA1/2 gene tests increased gradually. In total, 511 patients were included and BRCA1/2 mutations were observed in 143 (28.0%). Among 57 patients who received both germline and somatic tests, three (5.3%) showed discordant results from the two tests. Overall, no differences in progression-free survival (PFS; p=0.467) and overall survival (p=0.641) were observed between the BRCA mutation and wild-type groups; however, multivariate analyses identified BRCA1/2 mutation as an independent favorable prognostic factor for PFS (adjusted hazard ratio [aHR], 0.765; 95% confidence interval [CI], 0.593 to 0.987; p=0.040). In 389 patients with International Federation of Gynecology and Obstetrics stage III-IV, different results were shown depending on primary treatment strategy: while BRCA1/2 mutation significantly improved PFS in the subgroup of neoadjuvant chemotherapy (aHR, 0.619; 95% CI, 0.385 to 0.995; p=0.048), it did not affect patient PFS in the subgroup of primary debulking surgery (aHR, 0.759; 95% CI, 0.530 to 1.089; p=0.135).

CONCLUSION

BRCA1/2 mutations are frequently observed in patients with epithelial POFTCs, and such patients showed better PFS than did those harboring wild-type BRCA1/2.

Molecular profiles of BRCA1-associated ovarian cancer treated by platinum-based therapy: Analysis of primary, residual and relapsed tumors

Our study aimed to analyze the evolution of molecular portraits of BRCA1-driven ovarian cancer (OC) during treatment. BRCA1 loss-of-heterozygosity status (LOH) and exome profiles were investigated in serial OC samples from 13 patients, which included primary tumors (n = 11) obtained before neoadjuvant therapy (NACT) or at primary debulking surgery, residual post-NACT cancer tissues (n = 13) and tumor relapses (16 samples from 13 patients). Loss of the wild-type BRCA1 allele was detected in 11/11 (100%) primary tumors, 6/13 (46%) residual post-NACT OC samples and 15/16 (94%) OC relapses. Full tumor triplets were available for four patients undergoing NACT; whereas primary carcinomas from these patients demonstrated BRCA1 LOH, the retention of the wild-type allele was detected in all four post-NACT residual tumors. These four women provided to the study 5 recurrent OC samples; 4 out of 5 tumor relapses had BRCA1 LOH thus resembling BRCA1 status observed in primary but not residual OC tissues. TP53 mutation was detected in 12 out of 13 patients and was retained across all serial samples. OC relapses tended to acquire additional intragenic mutations in genes involved in cell migration, adhesion and cell junction assembly. BRCA1-driven OCs demonstrate the plasticity of BRCA1 status during the treatment course. NACT results in rapid selection of pre-existing BRCA1-proficient cells. However, BRCA1 proficiency appears to be disadvantageous in the absence of platinum exposure, as tumor relapses usually re-acquire BRCA1 LOH during therapy holidays.

Outcome-Related Differences in Gene Expression Profiles of High-Grade Serous Ovarian Cancers Following Neoadjuvant Chemotherapy

Large-scale genomic studies have detailed the molecular landscape of tumors from patients with high-grade serous ovarian cancers (HGSC) who underwent primary debulking surgery and correlated the identified subgroups to survival. In recent years, there is increased use of neoadjuvant chemotherapy (NACT) for patients with HGSC and while abundant data exist for patients who underwent primary debulking, little data are available on the cancer cells remaining after NACT that could lead to recurrences. We aimed to analyze gene expression profiles of NACT-treated HGSC tumor samples, and correlate them to treatment response and outcome. Tumor samples were collected from patients with stage III or IV HGSC (NACT cohort, N = 57) at the time of surgery and diagnosis (biopsy samples N = 8). Tumor content was validated by histologic examination and bioinformatics. Gene expression analysis was performed using a tailored NanoString-based assay, while sequencing was performed using MiSeq. A cross-validated survival classifier revealed patient clusters with either a "Better" or "Worse" prognostic outcome. The association with overall survival remained significant after controlling for clinical variables, and differential gene expression, gene set enrichment analyses, and the appropriate survival models were used to assess the associations between alterations in gene expression in cancer cells remaining after NACT and outcome. Pathway-based analysis of the differentially expressed genes revealed comparatively high levels of cell cycle and DNA repair gene expression in the poor outcome group. IMPLICATIONS: Our work suggests mRNA expression patterns in key genes following NACT may reflect response to treatment and outcome in patient with HGSC.

Mechanisms of acquired tumor drug resistance

Systemic therapy often results in the reduction of tumor size but rarely succeeds in eradicating all cancer cells. Drug efflux, persistence of cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT) and down-regulation of apoptosis are the most known general causes of therapy failure. Tumor escape from targeted compounds often involves pathway-specific mechanisms, which result in the restoration of the affected signaling cascade. The acquisition of drug resistance is mediated by mutations, changes in gene expression, alternative splicing, post-translational protein modifications, etc. Development of resistance to therapy may not necessary involve the emergence of new tumor clones: multiple studies demonstrate that even chemonaive neoplasms already have a small population of cells, which are capable of surviving therapeutic pressure and facilitating the disease progression. Use of combinations of cancer drugs, sequential therapy, adaptive therapy and topical ablation of drug-resistant malignant lumps may help to prolong the time to treatment failure. Many studies on mechanisms of drug resistance rely on the use of cell cultures and animal models. The development of approaches that allow efficient monitoring of the evolution of tumor phenotype in clinical setting presents a challenge.

Efficacy of Neoadjuvant Therapy With Cisplatin Plus Mitomycin C in BRCA1-Mutated Ovarian Cancer

OBJECTIVES

Cisplatin and mitomycin C exert high activity towards BRCA1-deficient cells. This study aimed to evaluate the efficacy of a combination of these drugs in hereditary BRCA1-associated ovarian cancer (OC).

METHODS

Twelve OC patients, who could not be treated by primary debulking surgery owing to extensive tumor spread, were given neoadjuvant cisplatin (100 mg/m) and mitomycin C (10 mg/m) every 4 weeks for 3 (n = 9), 2 (n = 2), or 4 (n = 1) cycles.

RESULTS

The decrease of tumor burden and complete surgical cytoreduction were achieved in all patients. Pathologic complete response, defined as the absence of tumor cells in surgically removed tissues, was observed in 2 (17%) of 12 cases. Retrospective analysis of 62 OC in BRCA1 mutation carriers subjected to conventional neoadjuvant chemotherapy schemes revealed 36 objective tumor responses (58%) and 37 instances (60%) of complete cytoreductive surgery; however, none of these patients demonstrated pathologic complete response.

CONCLUSIONS

The combination of cisplatin plus mitomycin C showed promising results in BRCA1-driven OC and therefore deserves further clinical evaluation.

BRCA1-associated and sporadic ovarian carcinomas: outcomes of primary cytoreductive surgery or neoadjuvant chemotherapy

OBJECTIVE

Tumors arising in BRCA1/2 mutation carriers are characterized by increased platinum sensitivity; however, it is unknown whether this feature should be considered while choosing between primary surgical versus systemic treatment. This study aimed to compare outcomes of ovarian cancer patients undergoing either primary surgery or interval cytoreduction based on BRCA1/2 status.

METHODS

The study included consecutive ovarian cancer patients, who were treated at the N.N. Petrov Institute of Oncology (St Petersburg, Russia) from 2000 to 2013 and who underwent complete or optimal cytoreductive surgery. A comparison of disease outcomes was performed for the total group of ovarian cancer patients as well as for 69 BRCA1-mutated and 151 sporadic high-grade serous advanced-stage ovarian carcinomas. Frequency comparisons were performed by Chi-square test or Fisher exact test. Disease-free interval and overall survival were analyzed by Mann-Whitney U-test and Kaplan-Meier method. Hazard ratios were calculated by Cox regression analysis.

RESULTS

The analysis included 283 consecutive patients who underwent optimal cytoreduction (size of residual tumor <1 cm (n=156)) or complete tumor excision (n=127) on primary surgery (n=168) or after neoadjuvant chemotherapy (n=115). 84 patients carried germline mutation in BRCA1 (n=77) or BRCA2 (n=7) genes, while 199 ovarian cancer patients were classified as sporadic. High-grade serous ovarian cancer patients treated with neoadjuvant chemotherapy had a lower disease-free interval compared with those undergoing primary surgery followed by adjuvant therapy (7.8 vs 14.2 months, p<0.001). This difference was attributed mainly to sporadic cases (5.1 vs 12.2 months, p<0.001), while BRCA1-associated cancers had a similar disease-free interval regardless of the sequence of treatments (12.5 vs 15.8 months, p=0.53). When treated with neoadjuvant chemotherapy, BRCA1-mutated patients had improved overall survival as compared with sporadic cases (45.7 vs 25.3 months, p=0.007), while patients subjected to primary surgery showed similar overall survival irrespective of BRCA1 status (54.6 vs 53.9 months, p=0.56). A total of 29/61 (48%) BRCA1/2-associated patients relapsed as a single local tumor; this was lower in sporadic cancer patients (38/134 (28%); p=0.01).

CONCLUSION

In BRCA1 mutation carriers, the oncologic outcomes are similar when comparing primary surgery versus neoadjuvant chemotherapy. In addition, BRCA1-mutation carriers often have a single site of disease when diagnosed with recurrent ovarian cancer.

Molecular Diagnostics in Clinical Oncology

There are multiple applications of molecular tests in clinical oncology. Mutation analysis is now routinely utilized for the diagnosis of hereditary cancer syndromes. Healthy carriers of cancer-predisposing mutations benefit from tight medical surveillance and various preventive interventions. Cancers caused by germ-line mutations often require significant modification of the treatment strategy. Personalized selection of cancer drugs based on the presence of actionable mutations has become an integral part of cancer therapy. Molecular tests underlie the administration of EGFR, BRAF, ALK, ROS1, PARP inhibitors as well as the use of some other cytotoxic and targeted drugs. Tumors almost always shed their fragments (single cells or their clusters, DNA, RNA, proteins) into various body fluids. So-called liquid biopsy, i.e., the analysis of circulating DNA or some other tumor-derived molecules, holds a great promise for non-invasive monitoring of cancer disease, analysis of drug-sensitizing mutations and early cancer detection. Some tumor- or tissue-specific mutations and expression markers can be efficiently utilized for the diagnosis of cancers of unknown primary origin (CUPs). Systematic cataloging of tumor molecular portraits is likely to uncover a multitude of novel medically relevant DNA- and RNA-based markers.

Accurate detection and quantification of epigenetic and genetic second hits in BRCA1 and BRCA2-associated hereditary breast and ovarian cancer reveals multiple co-acting second hits

BACKGROUND

This study characterizes the second hit spectrum in BRCA1 and BRCA2-associated breast and ovarian cancers at both gene loci to investigate if second hit mechanisms are mutually exclusive or able to coincide within the same tumor.

METHODS

Loss of heterozygosity, somatic point mutations and copy number alterations along with promoter methylation were studied in 56 breast and 15 ovarian cancers from BRCA1 and BRCA2 germline mutation carriers. A mathematical methodology was introduced to quantify the tumor cell population carrying a second hit.

RESULTS

Copy neutral LOH was the most prevalent LOH mechanism in this cohort (BC 69%, OC 67%). However, only 36% of BC and 47% of OC showed LOH in all cancerous cells. Somatic intragenic deletions and methylated subclones were also found in combination with (partial) loss of heterozygosity. Unequivocal deleterious somatic point mutations were not identified in this cohort.

CONCLUSION

Different mechanisms inactivating the wild type allele are present within the same tumor sample at various extents. Results indicate that BRCA1/2-linked breast and ovarian cancer cells are predominantly characterized by LOH, but harbor a complex combination of second hits at various frequencies.

"Lazarus Response" to Olaparib in a Virtually Chemonaive Breast Cancer Patient Carrying Gross BRCA2 Gene Deletion

This report describes an estrogen receptor-positive breast cancer patient, who relapsed at two and a half years after the completion of adjuvant chemotherapy while being on the aromatase inhibition. Based on the clinical evidence for potential sensitivity of the tumor to hormone ablation, everolimus was added to continuing exemestane treatment. Oral chemotherapy was administered at further disease progression, however, it lasted only for 10 days due to rapidly deteriorating condition of the patient. BRCA test was performed just before the failure of endocrine therapy and revealed a gross deletion within BRCA2 gene. Since the patient already developed contraindications to the standard chemotherapy, olaparib (300 mg twice a day) was given as a last hope option. The patient demonstrated a “Lazarus response”: the performance status and the results of the biochemical tests went back to the norm within first two weeks of treatment. Positron emission tomography-computed tomography (PET-CT) was performed at one month after the start of olaparib therapy, and revealed complete metabolic response for all multiple metastatic lesions located in the liver, bones, small pelvis, lungs, mediastinum, retroperitoneum, etc. Cytotoxic therapy and poly ADP-ribose polymerase (PARP) inhibitors are known to have virtually identical mechanisms of tumor escape from the treatment, which are confined to the restoration of BRCA proficiency within cancer cells. The pronounced tumor response to the treatment in this patient can be attributed to the lack of recent exposure to standard cytotoxic treatment as well as to the inability of tumors with gross BRCA rearrangements to restore BRCA function via secondary mutation. This observation calls for comprehensive evaluation of PARP inhibitors in chemonaive patients with hereditary cancer.