Targeting Mitochondria with ClpP Agonists as a Novel Therapeutic Opportunity in Breast Cancer

Breast cancer is the most frequently diagnosed malignancy worldwide and the leading cause of cancer mortality in women. Despite the recent development of new therapeutics including targeted therapies and immunotherapy, triple-negative breast cancer remains an aggressive form of breast cancer, and thus improved treatments are needed. In recent decades, it has become increasingly clear that breast cancers harbor metabolic plasticity that is controlled by mitochondria. A myriad of studies provide evidence that mitochondria are essential to breast cancer progression. Mitochondria in breast cancers are widely reprogrammed to enhance energy production and biosynthesis of macromolecules required for tumor growth. In this review, we will discuss the current understanding of mitochondrial roles in breast cancers and elucidate why mitochondria are a rational therapeutic target. We will then outline the status of the use of mitochondria-targeting drugs in breast cancers, and highlight ClpP agonists as emerging mitochondria-targeting drugs with a unique mechanism of action. We also illustrate possible drug combination strategies and challenges in the future breast cancer clinic.

Does previous history of cancer or atypia predict histologic upgrade for pure intraductal papillomas diagnosed via core biopsy? A study of 490 cases at a single institution

BACKGROUND

Management of pure intraductal papillomas (IDP) without atypia diagnosed on core needle biopsy (CNB) remains controversial given highly variable rates of upgrade in the literature.

AIM

We sought to identify clinical and histologic factors that predict upgrade to atypia or malignancy in a large population.

METHODS AND RESULTS

A retrospective review was performed of all cases of pure IDP diagnosed on CNB and then surgically excised at a single institution from 2008 to 2018. Clinical, radiologic, and pathologic factors were compared in the no upgrade, upgrade to atypia, or upgrade to cancer groups. Univariate analysis was performed comparing no upgrade and upgrade to cancer or atypia. Four hundred and thirty nine patients were identified with a total of 490 IDP and a median age of 50 years (range 16-85). Of these patients, 54 (12.3%) were upgraded to atypia after surgical excision and five (1.1%) were upgraded to cancer. The presence of multiple papillomas in a single patient was a significant predictor of upgrade to cancer or atypia (p < .01), as well as age over ≥55 years (p < .01) and a prior history of cancer (p < .01). No other clinical, radiologic and histologic factors were found to be significant predictors of upgrade. 40/439 (9.1%) patients in the total cohort had prior history of cancer, and of these, 2/40 (5%) were found to have a new cancer after excision.

CONCLUSIONS

In patients with pure IDP on CNB, the upgrade rate to malignancy was 1.1%, while 12.3% were upgraded to atypia. The clinical significance of identifying atypia in a papilloma is unknown, especially in a patient with a prior history of atypia or cancer. However, the majority of patients who were upgraded to either atypia or cancer had no prior history of high-risk or malignant breast disease and are therefore considered true clinical upgrades. As such excision for IDP should be considered.

Response in breast vs axilla after neoadjuvant treatment and implications for nonoperative management of invasive breast cancer

Improved imaging and neoadjuvant chemotherapy (NAT) have led to higher pathologic complete response rates (pCR) in patients with invasive breast cancer. This has questioned the necessity of surgery and axillary lymph node (ALN) dissection in these patients. Prospective clinical trials are implementing extensive core biopsies of the tumor bed of patients with clinical complete response as a means to identify and spare them breast surgery. In addition, it is anticipated that patients with pCR are most likely going to have no or minimal disease in ALN as well. To verify the feasibility of these trials, we performed a pathologic analysis of all our patients who have undergone NAT from 2009 to present. Using pathology data base, we identified 362 patients treated with neoadjuvant chemotherapy followed by surgery. Clinical and pathologic information including gross and microscopic descriptions as well as biomarker status was collected. pCR was 50% for patients with negative ALN pretreatment but only 28% for patients with positive ALN at diagnosis. Despite achieving pCR in the breast, up to 10% of patients with positive ALN and 1% with negative ALN had persistent disease. Eight percent of patients that were presumed to have no ALN disease either clinically and or by imaging were found to have metastatic carcinoma in ALN. The metastases were predominantly (80%) <5 mm, and not palpable on physical examination and or due to biopsy sampling error. pCR in breast and ALN directly correlated with tumor size, ALN disease, and Her2 positive and triple negative receptor phenotype. In breast cancer patients who are node positive at time of diagnosis with pCR in the breast after neoadjuvant chemotherapy, residual lymph node disease was very uncommon. Further study is warranted to select patients who may avoid breast and axillary surgery post neoadjuvant chemotherapy.

Adherence to NCCN Guidelines for Genetic Testing in Breast Cancer Patients: Who Are We Missing?

BACKGROUND

Genetic predisposition accounts for 5-10% of all breast cancers (BC) diagnosed. NCCN guidelines help providers identify appropriate candidates for counseling and testing. Concerns about underutilization of genetic testing have spurred interest in broader peri-diagnostic testing. We evaluated surgeon adherence to NCCN guidelines and studied patterns of testing in newly diagnosed BC patients.

METHODS

A total of 397 patients were identified with newly diagnosed BC treated at our institution between 2016 and 2017 with no prior genetic testing. Eligibility for genetic testing based on NCCN criteria, referral, and patient compliance were recorded.

RESULTS

In total, 212 of 397 (53%) met NCCN testing criteria. Fifty-nine of 212 (28%) patients went untested despite meeting one or more criteria. Fourteen of 59 (24%) of these were referred but did not comply. Most common criteria for meeting eligibility for testing both in the overall cohort and among missed patients were family history-based. Age > 45 years old and non-Ashkenazi Jewish descent were predictive of missed referral (p < 0.01). We identified pathogenic mutations in 16 of 153 (10%) patients who did undergo testing (11 (7%) BRCA1 or 2 and 5 (3%) with other predisposition gene mutations) or 16 of 397 (4%) among the overall group.

CONCLUSIONS

Our data highlight the underutilization of genetic testing. Even in the setting of a full-service breast center with readily available genetic counseling, there is a substantial miss rate for identifying eligible patients, related to assessment of family history, patient age, and ethnicity, as well as patient compliance. Broader peri-diagnostic testing should be considered, and higher compliance rates with patients referred should be sought.