Correlative studies of the Breast Cancer Index (HOXB13/IL17BR) and ER, PR, AR, AR/ER ratio and Ki67 for prediction of extended endocrine therapy benefit: a Trans-aTTom study.

BACKGROUND: Multiple clinical trials demonstrate consistent but modest benefit of adjuvant extended endocrine therapy (EET) in HR + breast cancer patients. Predictive biomarkers to identify patients that benefit from EET are critical to balance modest reductions in risk against potential side effects of EET. This study compares the performance of the Breast Cancer Index, BCI (HOXB13/IL17BR, H/I), with expression of estrogen (ER), progesterone (PR), and androgen receptors (AR), and Ki67, for prediction of EET benefit. METHODS: Node-positive (N+) patients from the Trans-aTTom study with available tissue specimen and BCI results (N = 789) were included. Expression of ER, PR, AR, and Ki67 was assessed by quantitative immunohistochemistry. BCI (H/I) gene expression analysis was conducted by quantitative RT-PCR. Statistical significance of the treatment by biomarker interaction was evaluated by likelihood ratio tests based on multivariate Cox proportional models, adjusting for age, tumor size, grade, and HER2 status. Pearson's correlation coefficients were calculated to evaluate correlations between BCI (H/I) versus ER, PR, AR, Ki67 and AR/ER ratio. RESULTS: EET benefit, measured by the difference in risk of recurrence between patients treated with tamoxifen for 10 versus 5 years, is significantly associated with increasing values of BCI (H/I) (interaction P = 0.01). In contrast, expression of ER (P = 0.83), PR (P = 0.66), AR (P = 0.78), Ki67 (P = 0.87) and AR/ER ratio (P = 0.84) exhibited no significant relationship with EET benefit. BCI (H/I) showed a very weak negative correlation with ER (r = - 0.18), PR (r = - 0.25), and AR (r = - 0.14) expression, but no correlation with either Ki67 (r = 0.04) or AR/ER ratio (r = 0.02). CONCLUSION: These findings are consistent with the growing body of evidence that BCI (H/I) is significantly predictive of response to EET and outcome. Results from this direct comparison demonstrate that expression of ER, PR, AR, Ki67 or AR/ER ratio are not predictive of benefit from EET. BCI (H/I) is the only clinically validated biomarker that predicts EET benefit.

Clinicopathological features and BRCA1 and BRCA2 mutation status in a prospective cohort of young women with breast cancer.

BACKGROUND: Breast cancer in young women is more likely to have higher risk features and be associated with germline BRCA1/BRCA2 mutations. We present the clinicopathologic features of breast cancers in a prospective cohort of young women, and associations between surrogate molecular subtype and BRCA1/BRCA2 mutation status. METHODS: Histopathological features, biomarker status, tumour stage and BRCA status were collected. Invasive tumours were categorised as luminal A-like (ER + and/or PR + , HER2-, grade 1/2), luminal B-like (ER + and/or PR + , HER2 + , or ER + and/or PR + , HER2-, and grade 3), HER2-enriched (ER/PR-, HER2 + ) or triple-negative. RESULTS: In all, 57.3% (654/1143) of invasive tumours were high grade. In total, 32.9% were luminal A-like, 42.4% luminal B-like, 8.3% HER2-enriched, and 16.4% triple-negative. Among different age groups, there were no differences in molecular phenotype, stage, grade or histopathology. 11% (131) of tumours were from BRCA mutation carriers; 64.1% BRCA1 (63.1% triple-negative), and 35.9% BRCA2 (55.3% luminal B-like). DISCUSSION: The opportunity to provide comparisons across young age groups, BRCA mutation status, surrogate molecular phenotype, and the identification of more aggressive hormone receptor-positive phenotypes in this population provides direction for future work to further understand and improve disparate outcomes for young women with luminal B-like cancers, particularly BRCA2-associated cancers, with potential implications for tailored prevention and treatment.

Performance of a novel protease-activated fluorescent imaging system for intraoperative detection of residual breast cancer during breast conserving surgery.

PURPOSE: Safe breast cancer lumpectomies require microscopically clear margins. Real-time margin assessment options are limited, and 20-40% of lumpectomies have positive margins requiring re-excision. The LUM Imaging System previously showed excellent sensitivity and specificity for tumor detection during lumpectomy surgery. We explored its impact on surgical workflow and performance across patient and tumor types. METHODS: We performed IRB-approved, prospective, non-randomized studies in breast cancer lumpectomy procedures. The LUM Imaging System uses LUM015, a protease-activated fluorescent imaging agent that identifies residual tumor in the surgical cavity walls. Fluorescent cavity images were collected in real-time and analyzed using system software. RESULTS: Cavity and specimen images were obtained in 55 patients injected with LUM015 at 0.5 or 1.0 mg/kg and in 5 patients who did not receive LUM015. All tumor types were distinguished from normal tissue, with mean tumor:normal (T:N) signal ratios of 3.81-5.69. T:N ratios were 4.45 in non-dense and 4.00 in dense breasts (p = 0.59) and 3.52 in premenopausal and 4.59 in postmenopausal women (p = 0.19). Histopathology and tumor receptor testing were not affected by LUM015. Falsely positive readings were more likely when tumor was present < 2 mm from the adjacent specimen margin. LUM015 signal was stable in vivo at least 6.5 h post injection, and ex vivo at least 4 h post excision. CONCLUSIONS: Intraoperative use of the LUM Imaging System detected all breast cancer subtypes with robust performance independent of menopausal status and breast density. There was no significant impact on histopathology or receptor evaluation.

Feasibility Study of a Novel Protease-Activated Fluorescent Imaging System for Real-Time, Intraoperative Detection of Residual Breast Cancer in Breast Conserving Surgery.

BACKGROUND: Obtaining tumor-free margins is critical to prevent recurrence after lumpectomy for breast cancer. Unfortunately, current approaches leave positive margins that require second surgeries in 20-40% of patients. We assessed the LUM Imaging System for real-time, intraoperative detection of residual tumor. METHODS: Breast lumpectomy cavity walls and excised specimens were assessed with the LUM Imaging System after 1 mg/kg intravenous LUM015, a protease-activatable fluorescent agent. Fluorescence at potential sites of residual tumor in lumpectomy cavity walls was evaluated intraoperatively with a sterile hand-held probe, with real-time predictive results displayed on a monitor intraoperatively, and later correlated with histopathology. RESULTS: In vivo lumpectomy cavities and excised specimens were imaged after LUM015 injection in 45 women undergoing breast cancer surgery. Invasive ductal and lobular cancers and intraductal cancer (DCIS) were included. A total of 570 cavity margin surfaces in 40 patients were used for algorithm development. Image analysis and display took approximately 1 s per 2.6-cm-diameter circular margin surface. All breast cancer subtypes could be distinguished from adjacent normal tissue. For all imaged cavity surfaces, sensitivity for tumor detection was 84%. Among 8 patients with positive margins after standard surgery, sensitivity for residual tumor detection was 100%; 2 of 8 were spared second surgeries because additional tissue was excised at sites of LUM015 signal. Specificity was 73%, with some benign tissues showing elevated fluorescent signal. CONCLUSIONS: The LUM015 agent and LUM Imaging System allow rapid identification of residual tumor in the lumpectomy cavity of breast cancer patients and may reduce rates of positive margins.

Correction to: Feasibility Study of a Novel Protease-Activated Fluorescent Imaging System for Real-Time, Intraoperative Detection of Residual Breast Cancer in Breast Conserving Surgery.

The article Feasibility Study of a Novel Protease-Activated Fluorescent Imaging System for Real-Time, Intraoperative Detection of Residual Breast Cancer in Breast Conserving Surgery, written by Barbara L. Smith et al., was originally published electronically on the publisher's internet portal on January 2, 2020, without open access.

An Analysis of Nipple Enhancement at Breast MRI with Radiologic-Pathologic Correlation.

Breast MRI is the most sensitive imaging modality for assessment of the nipple-areola complex (NAC), which is important both in cancer staging and in high-risk screening. However, the normal appearance of the nipple at MRI is not well defined because of a paucity of scientific literature on this topic. Hence, there is a lack of descriptive terminology and diagnostic criteria, which may account for the wide variability in interpretation among radiologists when assessing the NAC on MR images. In light of the current shift toward possible expanded use of abbreviated (ie, fast) breast MRI for screening in women at average risk for cancer in particular, and because an increasing number of women now undergo nipple-sparing mastectomy for therapeutic and/or prophylactic indications, careful assessment of the NAC at MRI is essential. In this article, the normal pattern of nipple enhancement at MRI is defined on the basis of findings observed in healthy individuals, normal nipple enhancement at MRI is correlated with the structural anatomy of the nipple at histopathologic analysis, and artifacts and pitfalls related to MRI of the NAC are reviewed. Understanding the normal range of nipple morphology and enhancement at MRI is important, as it enables radiologists to better differentiate between normal and abnormal nipple findings with increased diagnostic confidence. ©RSNA, 2018 See discussion on this article by Cohen and Holbrook .

Effectiveness and tolerability of neoadjuvant pertuzumab-containing regimens for HER2-positive localized breast cancer.

PURPOSE: Based on improvement in pathologic complete response (pCR) in the NeoSphere and TRYPHAENA studies, the FDA approved neoadjuvant pertuzumab for HER2+ localized breast cancer. These studies demonstrated high pCR rates with THP (docetaxel + HP), FEC (5-fluorouracil, epirubicin, and cyclophosphamide)-THP, and TCHP (docetaxel, carboplatin + HP). However, in the United States, doxorubicin/cyclophosphamide (AC) is favored over FEC despite no data comparing neoadjuvant AC-THP with AC-TH or TCHP. Here we report outcomes for patients with localized HER2+ breast cancer treated with pertuzumab-containing neoadjuvant regimens and AC-TH. METHODS: We reviewed clinicopathological characteristics of patients with HER2+ breast cancer (Stage I-III) treated with either a neoadjuvant pertuzumab-containing regimen or dose-dense (dd) AC-TH, from 2011 to 2016 at a large academic medical institution and two affiliated community sites. pCR was defined as ypT0/is ypN0. Fisher's exact test and logistic regression analysis were used for statistical analysis. RESULTS: In this study (N = 121), pCR was numerically higher with pertuzumab-based regimens, including ddAC-THP (60%), TCHP (63%), THP (55%), as compared with ddAC-TH (46%). THP resulted in significantly less cycle delays due to toxicity compared to the other regimens (p = 0.02). THP also resulted in the least dose reductions, lowest rate of hospitalization, and lowest rate of treatment discontinuation. CONCLUSIONS: Pertuzumab-based regimens, including THP, resulted in higher pCR rates as compared to ddAC-TH, with the THP regimen associated with the best tolerability among patients with localized HER2+ breast cancer. Given the various neoadjuvant regimens, additional studies are needed to determine optimal treatment sequencing and escalation/de-escalation strategies to personalize neoadjuvant regimens for localized HER2+ breast cancer.

Real-time, intraoperative detection of residual breast cancer in lumpectomy cavity walls using a novel cathepsin-activated fluorescent imaging system.

PURPOSE: Obtaining tumor-free surgical margins is critical to prevent recurrence in breast-conserving surgery but it remains challenging. We assessed the LUM Imaging System for real-time, intraoperative detection of residual tumor. METHODS: Lumpectomy cavity walls and excised specimens of breast cancer lumpectomy patients were assessed with the LUM Imaging System (Lumicell, Inc., Wellesley MA) with and without intravenous LUM015, a cathepsin-activatable fluorescent agent. Fluorescence at potential sites of residual tumor was evaluated with a sterile hand-held probe, displayed on a monitor and correlated with histopathology. RESULTS: Background autofluorescence was assessed in excised specimens from 9 patients who did not receive LUM015. In vivo lumpectomy cavities and excised specimens were then imaged in 15 women undergoing breast cancer surgery who received no LUM015, 0.5, or 1 mg/kg LUM015 (5 women per dose). Among these, 11 patients had invasive carcinoma with ductal carcinoma in situ (DCIS) and 4 had only DCIS. Image acquisition took 1 s for each 2.6-cm-diameter surface. No significant background normal breast fluorescence was identified. Elevated fluorescent signal was seen from invasive cancers and DCIS. Mean tumor-to-normal signal ratios were 4.70 ± 1.23 at 0.5 mg/kg and 4.22 ± 0.9 at 1.0 mg/kg (p = 0.54). Tumor was distinguished from normal tissue in pre-and postmenopausal women and readings were not affected by breast density. Some benign tissues produced fluorescent signal with LUM015. CONCLUSION: The LUM Imaging System allows rapid identification of residual tumor in the lumpectomy cavity of breast cancer patients and may reduce rates of positive margins.

Functional genomics reveal that the serine synthesis pathway is essential in breast cancer.

Cancer cells adapt their metabolic processes to drive macromolecular biosynthesis for rapid cell growth and proliferation. RNA interference (RNAi)-based loss-of-function screening has proven powerful for the identification of new and interesting cancer targets, and recent studies have used this technology in vivo to identify novel tumour suppressor genes. Here we developed a method for identifying novel cancer targets via negative-selection RNAi screening using a human breast cancer xenograft model at an orthotopic site in the mouse. Using this method, we screened a set of metabolic genes associated with aggressive breast cancer and stemness to identify those required for in vivo tumorigenesis. Among the genes identified, phosphoglycerate dehydrogenase (PHGDH) is in a genomic region of recurrent copy number gain in breast cancer and PHGDH protein levels are elevated in 70% of oestrogen receptor (ER)-negative breast cancers. PHGDH catalyses the first step in the serine biosynthesis pathway, and breast cancer cells with high PHGDH expression have increased serine synthesis flux. Suppression of PHGDH in cell lines with elevated PHGDH expression, but not in those without, causes a strong decrease in cell proliferation and a reduction in serine synthesis. We find that PHGDH suppression does not affect intracellular serine levels, but causes a drop in the levels of α-ketoglutarate, another output of the pathway and a tricarboxylic acid (TCA) cycle intermediate. In cells with high PHGDH expression, the serine synthesis pathway contributes approximately 50% of the total anaplerotic flux of glutamine into the TCA cycle. These results reveal that certain breast cancers are dependent upon increased serine pathway flux caused by PHGDH overexpression and demonstrate the utility of in vivo negative-selection RNAi screens for finding potential anticancer targets.

Apocrine Metaplasia Found at MR Biopsy: Is There Something to be Learned?

The purpose of this study was to determine (a) the frequency of apocrine metaplasia (ApoM) found on MR core biopsy of suspicious findings, and (b) to determine if there are specific MR imaging features that might obviate the need for biopsy. This HIPAA-compliant retrospective study was performed under IRB exemption for quality assurance studies. Patient demographics, MR imaging features, and pathology were reviewed. Breast lesions which underwent MR-guided biopsy, yielding ApoM on pathology analysis were included. Retrospective review of MR imaging features of these lesions was performed by two radiologists blinded to pathology results except for the presence of ApoM. Imaging features on MR assessed included location, size, morphology, T1 and T2 signals, and enhancement kinetics. Full pathology results were subsequently reviewed during data analysis. The pathology slides and imaging was subsequently reviewed by two fellowship trained radiologists and a breast pathologist to categorize the finding of ApoM into target lesion (imaging corresponds to size of lesion on pathology) versus incidental lesion. Target lesion characteristics were assessed to determine specific MRI features of ApoM. Between January 2011 to November 2012, 155 distinct breast lesions suspicious for malignancy successfully underwent MR-guided biopsy. Of the 155 lesions biopsied, 123 (79%) were benign and 32 (21%) were malignant. Of the 123 benign biopsies, ApoM was found in 57 (46%), of which 35 (61%) had no associated atypia and 22 (39%) had associated atypia. Of the 32 malignant biopsies, three (9%) had associated ApoM (DCIS in two cases and DCIS/LCIS in one case). Of the 60 cases with ApoM, only 11 (18.3%) were target lesions and 49 were incidental lesions (81.7%). Of the 60 cases with ApoM, 35 (58%) were masses (average size 0.8 cm for both with or without atypia) and 25 (42%) were nonmass enhancement (NME) (average size 2.1 cm with and 1.0 cm without atypia). Only five (14%) of 35 masses demonstrated spiculated margins, of which four were associated with atypia (80%). Of 22 lesions with atypia or other high-risk lesion, 14 (64%) were masses, most commonly with irregular margins (64%). Of the 12 T2 hyperintense lesions, only two (1.7)% had associated atypia or high-risk lesion, and none were associated with malignancy. Of the 11 target lesions, seven were T2 hyperintense. Enhancement kinetics were variable: 30 (50%) showed mixed persistent and plateau kinetics, eight (13%) persistent delayed enhancement, 10 (17%) plateau kinetics, four (7%) washout kinetics, and eight (13%) were below threshold for kinetic analysis. ApoM is a common benign pathologic result at MR-guided core biopsy for both masses and NME accounting for 39% of all biopsy results in this series. Although there is considerable variability in imaging characteristics on MR, our results suggest biopsy may be safely obviated for lesions that are subcentimeter T2 hyperintense areas of NME and short term follow-up imaging may be a reasonable alternative for these lesions.

A Study of the Growth Patterns of Breast Carcinoma Using 3D Reconstruction: A Pilot Study.

Lumpectomy with microscopically clear margins is a safe and effective approach for surgical management of breast carcinoma. Margins are positive for tumor in 18-50% of lumpectomies, as it is not possible to accurately determine the shape or microscopic borders of a tumor preoperatively or intraoperatively. We examined the 3D microanatomy and growth patterns of common breast carcinoma subtypes to provide guidance for lumpectomy surgery. Prospective consent was obtained for the use of excess tissue from patients undergoing lumpectomy or mastectomy for breast carcinoma. Tissue blocks from nine breast carcinomas were serially sectioned. Hematoxylin and eosin-stained slides at 100 µm intervals were scanned using a Nanozoomer (Hamamatsu, Japan) microscopic-resolution scanner. Three-dimensional reconstructions of tumors were created from scanned images using Reconstruct, open-access software. Breast carcinoma subtypes demonstrated characteristic growth patterns within breast tissue, which may have implications for lumpectomy surgery. Invasive ductal carcinomas showed a spherical shape, with a spiculated surface representing tumor cells infiltrating into surrounding parenchyma. Ductal carcinoma in situ appeared to spread along the duct system, creating dilated, tortuous, tumor-filled ducts. The invasive lobular carcinomas examined had a haphazard, linear, infiltrative growth pattern, different from the shape seen in ductal carcinomas. Our preliminary work suggests that invasive ductal and invasive lobular carcinomas appear to have distinct growth patterns in three dimensions and ductal carcinoma in situ appears to grow in a linear fashion along the duct network. The microanatomy studies described have the potential to guide refinements in breast lumpectomy technique.

Hypermutable DNA chronicles the evolution of human colon cancer.

Intratumor genetic heterogeneity reflects the evolutionary history of a cancer and is thought to influence treatment outcomes. Here we report that a simple PCR-based assay interrogating somatic variation in hypermutable polyguanine (poly-G) repeats can provide a rapid and reliable assessment of mitotic history and clonal architecture in human cancer. We use poly-G repeat genotyping to study the evolution of colon carcinoma. In a cohort of 22 patients, we detect poly-G variants in 91% of tumors. Patient age is positively correlated with somatic mutation frequency, suggesting that some poly-G variants accumulate before the onset of carcinogenesis during normal division in colonic stem cells. Poorly differentiated tumors have fewer mutations than well-differentiated tumors, possibly indicating a shorter mitotic history of the founder cell in these cancers. We generate poly-G mutation profiles of spatially separated samples from primary carcinomas and matched metastases to build well-supported phylogenetic trees that illuminate individual patients' path of metastatic progression. Our results show varying degrees of intratumor heterogeneity among patients. Finally, we show that poly-G mutations can be found in other cancers than colon carcinoma. Our approach can generate reliable maps of intratumor heterogeneity in large numbers of patients with minimal time and cost expenditure.

A developmentally regulated inducer of EMT, LBX1, contributes to breast cancer progression.

Epithelial-to-mesenchymal transition (EMT) plays an important role during normal embryogenesis, and it has been implicated in cancer invasion and metastasis. Here, we report that Ladybird homeobox 1 (LBX1), a developmentally regulated homeobox gene, directs expression of the known EMT inducers ZEB1, ZEB2, Snail1, and transforming growth factor beta2 (TGFB2). In mammary epithelial cells, overexpression of LBX1 leads to morphological transformation, expression of mesenchymal markers, enhanced cell migration, increased CD44(high)/CD24(low) progenitor cell population, and tumorigenic cooperation with known oncogenes. In human breast cancer, LBX1 is up-regulated in the unfavorable estrogen receptor (ER)/progesterone (PR)/HER2 triple-negative basal-like subtype. Thus, aberrant expression of LBX1 may lead to the activation of a developmentally regulated EMT pathway in human breast cancer.

Spectrally encoded confocal microscopy for diagnosing breast cancer in excision and margin specimens.

A large percentage of breast cancer patients treated with breast conserving surgery need to undergo multiple surgeries due to positive margins found during post-operative margin assessment. Carcinomas could be removed completely during the initial surgery and additional surgery avoided if positive margins can be determined intraoperatively. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that has a potential to rapidly image the entire surgical margin at subcellular resolution and accurately determine margin status intraoperatively. In this study, in order to test the feasibility of using SECM for intraoperative margin assessment, we have evaluated the diagnostic accuracy of SECM for detecting various types of breast cancers. Forty-six surgically removed breast specimens were imaged with an SECM system. Side-by-side comparison between SECM and histologic images showed that SECM images can visualize key histomorphologic patterns of normal/benign and malignant breast tissues. Small (500 µm × 500 µm) spatially registered SECM and histologic images (n=124 for each) were diagnosed independently by three pathologists with expertise in breast pathology. Diagnostic accuracy of SECM for determining malignant tissues was high, average sensitivity of 0.91, specificity of 0.93, positive predictive value of 0.95, and negative predictive value of 0.87. Intra-observer agreement and inter-observer agreement for SECM were also high, 0.87 and 0.84, respectively. Results from this study suggest that SECM may be developed into an intraoperative margin assessment tool for guiding breast cancer excisions.

Breast fine needle aspiration continues to be relevant in a large academic medical center: experience from Massachusetts General Hospital.

Fine needle aspiration (FNA) is increasingly being supplanted by core needle biopsy. However, breast surgeons continue to rely on FNA at our institution. This retrospective study evaluated breast FNA for its diagnostic accuracy and breast cancer biomarker testing utility. All breast FNAs performed at Massachusetts General Hospital 2009-2015 were reviewed. Cytology diagnoses were compared with subsequent tissue or clinical diagnoses. Immunohistochemistry and fluorescence in situ hybridization (FISH) results using formalin-fixed paraffin-embedded (FFPE) cell blocks and histologic tissue blocks were compared. 1654 consecutive breast FNAs were included. Breast FNA demonstrated the following diagnostic performance: positive predictive value of malignant cytology diagnosis 100 %, negative predictive value of benign cytology diagnosis 97.5 %, complete sensitivity 91.6 %, and specificity 95.5 %. Concordance rates for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) immunohistochemistry, and HER2 FISH were 98.2 % (κ = 0.95, p < 0.001), 100.0 % (κ = 1.000, p < 0.001), 83.1 % (κ = 0.69, p < 0.001), and 93.5 % (κ = 0.785, p < 0.001), respectively. Review of consecutive breast FNAs in a large cohort confirmed the excellent accuracy of this biopsy technique for breast lesion diagnosis. FNA FFPE cell blocks collected in the course of routine clinical care are adequate, practical, and reliable for breast cancer biomarker testing.

Molecular Phenotype of Breast Cancer According to Time Since Last Pregnancy in a Large Cohort of Young Women.

BACKGROUND: The increase in breast cancer risk during pregnancy and postpartum is well known; however, the molecular phenotype of breast cancers occurring shortly after pregnancy has not been well studied. Given this, we investigated whether nulliparity and the time interval since pregnancy among parous women affects the breast cancer phenotype in young women. MATERIALS AND METHODS: We examined molecular phenotype in relation to time since pregnancy in a prospective cohort of 707 young women (aged ≤40 years) with breast cancer. Parity was ascertained from study questionnaires. Using tumor histologic grade on central review and biomarker expression, cancers were categorized as luminal A- or B-like, HER2 enriched, and triple negative. RESULTS: Overall, 32% were luminal A-like, 41% were luminal B-like, 9% were HER2 enriched, and 18% were triple negative. Although, numerically, patients diagnosed >5 years after pregnancy had more luminal A-like subtypes than women with shorter intervals since pregnancy, there was no evidence of a relationship between these intervals and molecular subtypes once family history of breast cancer and age at diagnosis were considered. CONCLUSION: Distribution of breast cancer molecular phenotype did not differ significantly among young women by parity or time interval since parturition when important predictors of tumor phenotype such as age and family history were considered. IMPLICATIONS FOR PRACTICE: Distribution of breast cancer molecular phenotype did not differ among parous young women by time interval since pregnancy. The implication of these findings for clinical practice suggests that pregnancy-associated breast cancers may be seen up to 5 years beyond parturition.

Homeobox B9 induces epithelial-to-mesenchymal transition-associated radioresistance by accelerating DNA damage responses.

Homeobox 9 (HOXB9), a nontransforming transcription factor overexpressed in breast cancer, alters tumor cell fate and promotes tumor progression and metastasis. Here we show that HOXB9 confers resistance to ionizing radiation by promoting DNA damage response. In nonirradiated cells, HOXB9 induces spontaneous DNA damage, phosphorylated histone 2AX and p53 binding protein 1 foci, and increases baseline ataxia telangiectasia mutated (ATM) phosphorylation. Upon ionizing radiation, ATM is hyperactivated in HOXB9-expressing cells during the early stages of the double-stranded DNA break (DSB) response, accelerating accumulation of phosphorylated histone 2AX, mediator of DNA-damage checkpoint 1, and p53 binding protein 1, at DSBs and enhances DSB repair. The effect of HOXB9 on the response to ionizing radiation requires the baseline ATM activity before irradiation and epithelial-to-mesenchymal transition induced by TGF-ß, a HOXB9 transcriptional target. Our results reveal the impact of a HOXB9-TGF-ß-ATM axis on checkpoint activation and DNA repair, suggesting that TGF-ß may be a key factor that links tumor microenvironment, tumor cell fate, DNA damage response, and radioresistance in a subset of HOXB9-overexpressing breast tumors.

A 92-gene cancer classifier predicts the site of origin for neuroendocrine tumors.

A diagnosis of neuroendocrine carcinoma is often morphologically straight-forward; however, the tumor site of origin may remain elusive in a metastatic presentation. Neuroendocrine tumor subtyping has important implications for staging and patient management. In this study, the novel use and performance of a 92-gene molecular cancer classifier for determination of the site of tumor origin are described in a series of 75 neuroendocrine tumors (44 metastatic, 31 primary; gastrointestinal (n=12), pulmonary (n=22), Merkel cell (n=10), pancreatic (n=10), pheochromocytoma (n=10), and medullary thyroid carcinoma (n=11)). Formalin-fixed, paraffin-embedded samples passing multicenter pathologist adjudication were blinded and tested by a 92-gene molecular assay that predicts tumor type/subtype based upon relative quantitative PCR expression measurements for 87 tumor-related and 5 reference genes. The 92-gene assay demonstrated 99% (74/75; 95% confidence interval (CI) 0.93-0.99) accuracy for classification of neuroendocrine carcinomas and correctly subtyped the tumor site of origin in 95% (71/75; 95% CI 0.87-0.98) of cases. Analysis of gene expression subsignatures within the 92-gene assay panel showed 4 genes with promising discriminatory value for tumor typing and 15 genes for tumor subtyping. The 92-gene classifier demonstrated excellent accuracy for classifying and determining the site of origin in tumors with neuroendocrine differentiation. These results show promise for use of this test to aid in classifying neuroendocrine tumors of indeterminate primary site, particularly in the metastatic setting.

Management of positive sub-areolar/nipple duct margins in nipple-sparing mastectomies.

We evaluated management of positive sub-areolar/nipple duct margins in nipple-sparing mastectomies (NSM) at our institution. Retrospective chart review of all NSM from January 2007 to April 2012 was performed and patient, tumor, and treatment information was collected. Sub-areolar/nipple duct margins included ductal tissue from within the nipple. Of 438 NSM, 22 (5%) had positive sub-areolar/nipple duct margins; 21 of 220 cancer-bearing breasts (10%) and 1 of 218 prophylactic mastectomies (0.5%). Positive margins included four with invasive lobular carcinoma and 18 with ductal carcinoma in situ (DCIS). Management included removal of eight nipples and nine nipple areola complexes (NAC). Four of 17 nipple/NAC specimens had evidence of residual DCIS and none had residual invasive cancer. The majority of nipple/NAC specimens excised for a positive margin had no residual malignancy. Future studies are needed to determine the extent of NAC tissue removal required for positive margins.