Clinicopathologic Predictors of Clinical Outcomes in Mammary Adenoid Cystic Carcinoma: A Multi-institutional Study.

Adenoid cystic carcinoma (AdCC) is an uncommon type of invasive breast carcinoma with a favorable prognosis. However, some cases are aggressive. The study aims to define the clinicopathologic predictors of outcome. Clinical, radiological, and pathologic variables were recorded for 76 AdCC cases from 11 institutions. The following histologic characteristics were evaluated by the breast pathologist in each respective institution, including Nottingham grade (NG), percentages of various growth patterns (solid, cribriform, trabecular-tubular), percentage of basaloid component, tumor borders (pushing, infiltrative), perineural invasion, lymphovascular invasion, necrosis, and distance from the closest margin. Various grading systems were evaluated, including NG, salivary gland-type grading systems, and a new proposed grading system. The new grading system incorporated the growth pattern (percent solid, percent cribriform), percent basaloid morphology, and mitotic count using the Youden index criterion. All variables were correlated with recurrence-free survival. Nineteen (25%) women developed local and/or distant recurrence. Basaloid morphology (≥25% of the tumor) was identified in 20 (26.3%) cases and a solid growth pattern (using ≥60% cutoff) in 22 (28.9%) cases. In the univariate analysis, the following variables were significantly correlated with worse recurrence-free survival: solid growth pattern, basaloid morphology, lymphovascular invasion, necrosis, perineural invasion, and pN-stage. In the multivariate analysis including basaloid morphology, pN-stage, lymphovascular invasion, and perineural invasion, basaloid morphology was statistically significant, with a hazard ratio of 3.872 (95% CI, 1.077; 13.924; P =.038). The NG and the new grading system both correlated with recurrence-free survival. However, grade 2 had a similar risk as grade 3 in the NG system and a similar risk as grade 1 in the new grading system. For solid growth patterns and basaloid morphology, using a 2-tier system with 1 cutoff was better than a 3-tier system with 2 cutoffs. Basaloid morphology and solid growth pattern have prognostic values for AdCC, with a 2-tier grading system performing better than a 3-tier system.

PTGES3 is a Putative Prognostic Marker in Breast Cancer.

BACKGROUND: The COX/prostaglandin (COX/PG) pathway plays a role in cancer pathogenesis via the production of prostaglandin E2 (PGE2). In breast cancer, the expression patterns of the COX/PG pathway enzymes involved in PGE2 synthesis are not well defined. MATERIALS AND METHODS: Using the Cancer Genome Atlas data, we analyzed the expression patterns of cyclooxygenases, COX1 (PTGS1) and COX2 (PTGS2), and four downstream enzymes of the COX/prostaglandin pathway - PTGS3 (PTGDS), PTGES1, PTGES2 and PTGES3 - in invasive breast cancer. The Clinical Proteomic Tumor Analysis Consortium database was used to determine the expression of these six genes at the protein level. Existing single-cell RNA sequencing data were used to evaluate the expression of the six COX/PG genes in luminal and basal epithelial cells from normal breast tissues. Cox regression Kaplan-Meier adjusted survival analyses were performed to evaluate the association of COX/PG pathway genes in overall survival using the TCGA data. Finally, we utilized the Tumor Immune Estimation Resource to correlate the expression of these six COX/PG genes with tumor infiltrating immune cell number. RESULTS: COX1, COX2 and PTGES3 were significantly upregulated at the protein level in breast cancer compared to normal tissues (P < 0.005). However, only PTGES3 expression was elevated at both the mRNA and protein level in breast cancer (P < 0.0005). PTGES3 is the most highly expressed enzymes within the COX/PG pathway in both luminal and basal epithelial cells in normal breast tissues. Using Cox Regression Kaplan-Meier survival analysis, PTGES3 expression had a significant inverse prognostic association with breast cancer survival [HR >1.43, P = 0.0057]. Elevated PTGES3 expression within the tumor microenvironment significantly correlated with CD8+ T cell abundance, suggesting a possible immunomodulatory role of PTGES3 in the tumor microenvironment. CONCLUSIONS: PTGES3, a terminal synthetase in the COX/prostaglandin pathway, is a putative prognostic marker in breast cancer.

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.

Insulin resistance contributes to racial disparities in breast cancer prognosis in US women.

BACKGROUND: Racial disparities in breast cancer survival between Black and White women persist across all stages of breast cancer. The metabolic syndrome (MetS) of insulin resistance disproportionately affects more Black than White women. It has not been discerned if insulin resistance mediates the link between race and poor prognosis in breast cancer. We aimed to determine whether insulin resistance mediates in part the association between race and breast cancer prognosis, and if insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R) expression differs between tumors from Black and White women. METHODS: We conducted a cross-sectional, multi-center study across ten hospitals. Self-identified Black women and White women with newly diagnosed invasive breast cancer were recruited. The primary outcome was to determine if insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR), mediated the effect of race on prognosis using the multivariate linear mediation model. Demographic data, anthropometric measurements, and fasting blood were collected. Poor prognosis was defined as a Nottingham Prognostic Index (NPI) > 4.4. Breast cancer pathology specimens were evaluated for IR and IGF-1R expression by immunohistochemistry (IHC). RESULTS: Five hundred fifteen women were recruited (83% White, 17% Black). The MetS was more prevalent in Black women than in White women (40% vs 20%, p < 0.0001). HOMA-IR was higher in Black women than in White women (1.9 ± 1.2 vs 1.3 ± 1.4, p = 0.0005). Poor breast cancer prognosis was more prevalent in Black women than in White women (28% vs 15%. p = 0.004). HOMA-IR was positively associated with NPI score (r = 0.1, p = 0.02). The mediation model, adjusted for age, revealed that HOMA-IR significantly mediated the association between Black race and poor prognosis (ß = 0.04, 95% CI 0.005-0.009, p = 0.002). IR expression was higher in tumors from Black women than in those from White women (79% vs 52%, p = 0.004), and greater IR/IGF-1R ratio was also associated with higher NPI score (IR/IGF-1R >  1: 4.2 ± 0.8 vs IR/IGF-1R = 1: 3.9 ± 0.8 vs IR/IGF-1R < 1: 3.5 ± 1.0, p < 0.0001). CONCLUSIONS: In this multi-center, cross-sectional study of US women with newly diagnosed invasive breast cancer, insulin resistance is one factor mediating part of the association between race and poor prognosis in breast cancer.

Iatrogenic issues in breast pathology.

Modern breast imaging techniques include digital mammography, 3-dimensional tomography, high-resolution ultrasound, and magnetic resonance imaging. Each of these has enabled the diagnosis of ever smaller, largely non-palpable lesions, not all of which require surgery. As these techniques evolved, so too did methods of accurately targeting and sampling the lesions, necessitating methods to mark the areas should surgical localization be needed. These methods have introduced heretofore unseen histologic changes to both breast tissue and lymph nodes, especially sentinel lymph nodes. These changes are the topic of this review.

The clinical significance of metastatic breast carcinoma to intramammary lymph node.

The incidence of involved intramammary lymph node (intra-MLN) with breast carcinoma (BC) is rare. Its clinical significance and impact on the clinical decision making is unclear. A total of 113 BC cases with at least one positive intra-MLN were collected from 11 academic institutions. The inclusion criteria were subsequent axillary lymph node dissection, and the availability of information on T-stage, size of node metastasis, extranodal extension status, biomarkers status, and clinical follow-up. Stage 4 cases and/or neo-adjuvant treated patients were excluded. AJCC TN-stage was calculated twice, with and without intra-MLN. Five-year overall survival (OS) and relapse (local and/or distant)-free survival (RFS) were calculated and correlated with the clinicopathologic variables. Excluding intra-MLN, TN-stage correlated with OS (P = .016) but not with RFS (P = .19). However, when intra-MLN was included, TN-stage correlated with both OS (P < .001) and RFS (P = .016). In the multivariate analysis, when intra-MLN was excluded, only radiation therapy (RT) correlated with RFS (HR = 0.19, 95% CI: 0.054-0.66, P = .009). However, when intra-MLN was included in the TN-stage both RT (HR = 0.13, 95% CI: 0.04-0.45, P = .001) and TN-stage 3 (HR = 8.92, 95% CI: 1.47-54, P = .017) correlated with RFS. Tumor multifocality was the only variable correlated with OS when the intra-MLN involvement was excluded. When intra-MLN was included, multifocality became insignificant but TN-stage 3 correlated with OS (HR = 8.59, 95% CI: 1.06-69.71, P = .044). Positive intra-MLN is an independent factor in predicting both RFS and OS.

MYB rearrangement and immunohistochemical expression in adenomyoepithelioma of the breast: a comparison with adenoid cystic carcinoma.

AIMS: Adenomyoepithelioma (AME) and adenoid cystic carcinoma (ACC) of the breast have been noted to occur simultaneously, raising the possibility that AME may represent a related or precursor lesion to ACC. ACC frequently harbours genetic rearrangement of the MYB gene. We sought to clarify the relationship between AME and ACC by comparing their rates of MYB expression by IHC and MYB rearrangement by FISH. METHODS AND RESULTS: IHC and FISH for MYB rearrangement were performed on paraffin-embedded sections of 11 breast ACCs, 11 non-breast ACCs and 11 breast-AMEs. Using FISH, five of eight (63%) interpretable breast ACCs demonstrated MYB gene rearrangement. Nine of 11 (81%) breast ACCs demonstrated MYB expression (range = 20-95%). Of the three FISH-negative breast ACCs, two were solid variant and demonstrated strong MYB expression by IHC. Of the 10 interpretable non-breast ACCs, six showed MYB rearrangement, all of which were conventional type. Nine of these 11 (81%) cases showed MYB immunoexpression (range = 10-90%), including three solid-variant cases which were negative by FISH. No MYB rearrangements were detected by FISH in 10 interpretable AMEs. However, three of 11 cases (27%) showed weak to moderate MYB expression by IHC (range = 10-40%). CONCLUSIONS: Our results indicate that AMEs do not harbour MYB gene rearrangement. IHC for MYB may be helpful in diagnosing FISH-negative cases of ACC, particularly the diagnostically more difficult solid variants. However, weak to moderate MYB expression in a subset of AMEs highlights not only a potential diagnostic pitfall, but also shared pathophysiology with ACC worth investigating further at the genomic level.

Iatrogenically false positive sentinel lymph nodes in breast cancer: Methods of recognition and evaluation.

With the introduction of sentinel lymph node (SLN) biopsy as a standard procedure for staging clinically node negative breast cancer patients, meticulous pathologic evaluation of SLNs by serial sections and/or immunohistochemistry for cytokeratins has become commonplace in order to detect small volume metastases (isolated tumor cells and micrometastases). This practice has also brought to the fore the concept of iatrogenically false positive sentinel nodes secondary to epithelial displacement produced largely by preoperative needling procedures. While this concept is well described in the clinical and pathologic literature, it is, in our experience, still under-recognized, with such lymph nodes frequently incorrectly diagnosed as harboring true metastases, possibly resulting in unwarranted further surgery and/or chemotherapy. This review discusses the concept of displaced epithelium in the histologic evaluation of breast surgical specimens and provides a stepwise approach to the correct identification of iatrogenically transported displaced epithelial cells in sentinel lymph nodes.

Metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer outcomes: hypothesis and proposed pathways.

BACKGROUND: Women with obesity and type 2 diabetes (T2D) are at greater risk of dying from breast cancer than women without these conditions. Obesity and T2D are associated with insulin resistance and endogenous hyperinsulinemia and are more common in Black women. There is increasing disparity in breast cancer mortality between Black and White women in the USA. We hypothesize that insulin resistance and endogenous hyperinsulinemia in Black women with breast cancer contribute to their greater breast cancer mortality and are associated with increased insulin receptor signalling in tumours. METHODS: We will recruit 350 Black women and 936 White women with newly diagnosed breast cancer. We will determine the presence or absence of the metabolic syndrome/pre-diabetes and insulin resistance by measuring body mass index, waist circumference, lipids, blood pressure, glucose, insulin-like growth factor binding protein 1 and insulin. Breast cancer prognosis will be determined by a Nottingham Prognostic Index (NPI), with poor prognosis being defined as NPI >4.4. Tumour insulin receptor signalling will be determined by immunohistochemistry. Insulin receptor subtype expression will be measured using Nanostring. Analysis of these factors will determine whether endogenous hyperinsulinemia is associated with a worse prognosis in Black women than White women and increased tumour insulin receptor signalling. CONCLUSIONS: The results of this study will determine if the metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer mortality. It may provide the basis for targeting systemic insulin resistance and/or tumour insulin receptor signalling to reduce racial disparities in breast cancer mortality. Copyright © 2016 John Wiley & Sons, Ltd.

The clinical significance of internal mammary lymph node (IMLN) biopsy during autologous reconstruction in breast cancer patients.

The clinical significance of IMLN metastases in breast cancer is controversial. Although IMLN status is an integral part of current AJCC staging of breast cancer, the elective sampling of IMLN is not part of routine surgery for breast cancer. The purpose of this study was to determine the incidence of IMLN metastases, associated risk factors if any, and its impact on further management and outcome. We retrospectively studied 470 cases that underwent autologous reconstruction surgery between 2002 and 2014. Of 470 cases, 157 breast cancer cases had histology-confirmed IMLN removal during the reconstruction. Only 9 patients (6 %) showed IMLN metastases as compared to 45 (34 %) that showed axillary nodal metastases (p < 0.01). Interestingly, 4 patients had metastases limited to IMLN without any metastases to axillary nodes. IMLN metastasis was significantly associated with age <40 years, lymphovascular invasion, and negative PR status. IMLN metastasis resulted in upstaging of 2 patients from stage I to III, and 1 from stage II to III. Five patients received additional chest wall radiation to target the positive IMLNs. Nine of 157 (6 %) patients with IMLN removal during reconstruction had loco-regional recurrence/metastasis as compared to 20 of 293 (7 %) patients without IMLN removal (p > 0.05) (follow-up, 1-134 months). The overall rate of IMLN metastases (6 %) is much lower than the rate of axillary node metastases. Selective biopsy of IMLNs in patients with breast cancer, especially if younger than 40 years, and with lymphovascular invasion and negative PR status, may guide adjuvant treatment.

Are cytokeratin-positive cells in sentinel lymph nodes of patients with invasive breast carcinomas up to 5 mm usually insignificant?

AIMS: It is known that sentinel lymph nodes (SLN) may be falsely positive due to displaced epithelial cells, particularly in cases with an underlying intraductal papilloma. Given the low metastatic rate in pT1a carcinomas, we aimed to investigate the effect of this phenomenon on staging. METHODS AND RESULTS: Using morphology and immunohistochemistry, we classified the epithelial cells in the SLN in 39 cases of pT1a carcinoma as positive for carcinoma in six, negative in 26 and undetermined in seven. Comparative morphology and immunohistochemistry (using oestrogen receptor, ER) showed complete concordance between the primary carcinoma and SLN in the positive cases, and discordance in the negative cases. The primary tumours in the negative cases were ER-positive except one, in contrast to the SLN cytokeratin-positive (CK(+) ) cells, which were ER-negative. The exception was a case with a Her2-positive primary, in which the SLN CK(+) cells did not stain for Her2. In these cases considered SLN-negative, either displacement (19 cases) or an intraductal papilloma (20 cases) was identified. Two cases showed displacement of benign and malignant cells in the biopsy. Seven cases were indeterminate due to the small number of SLN CK(+) cells, precluding comparison with the primary. CONCLUSION: Given the low rate of metastases in pT1a carcinomas, the significance of SLN CK(+) cells should be resolved by comparative morphology and immunohistochemistry to prevent erroneous upstaging.

Re-evaluating the role of sentinel lymph node biopsy in microinvasive breast carcinoma.

The role of sentinel lymph node biopsy in microinvasive breast carcinoma is unclear. We examined the incidence of lymph node metastasis in patients with microinvasive carcinoma who underwent surgery at our institution. Retrospective review of our pathology database was performed (1994-2012). Of 7000 patients surgically treated for invasive breast carcinoma, 99 (1%) were classified as microinvasive carcinoma. Axillary staging was performed in 81 patients (64, sentinel lymph node biopsy; 17, axillary lymph node excision). Seven cases (9%) showed isolated tumor/epithelial cells in sentinel nodes. Three of these seven cases showed reactive changes in lymph nodes, papillary lesions in the breast with or without displaced epithelial cells within biopsy site tract, or immunohistochemical (estrogen receptor, progesterone receptor, and HER2) discordance between the primary tumor in the breast and epithelial cells in the lymph node, consistent with iatrogenically transported epithelial cells rather than true metastasis. The remaining four cases included two cases, each with a single cytokeratin-positive cell in the subcapsular sinus detected by immunohistochemistry only, and two cases with isolated tumor cells singly and in small clusters (<20 cells per cross-section) by hematoxylin and eosin and immunohistochemistry. The exact nature of cytokeratin-positive cells in the former two cases could not be determined and might still have represented iatrogenically displaced cells. In the final analysis, only two cases (3%) had isolated tumor cells. Three of these four cases had additional axillary lymph nodes excised, which were all negative for tumor cells. At a median follow-up of 37 months (range 6-199 months), none of these patients had axillary recurrences. Our results show very low incidence of sentinel lymph node involvement (3%), only as isolated tumor cells, in microinvasive carcinoma patients. None of our cases showed micrometastases or macrometastasis. We recommend reassessment of the routine practice of sentinel lymph node biopsy in patients with microinvasive carcinoma.

MARCH2, a Novel Oncogene-regulated SNAIL E3 Ligase, Suppresses Triple-negative Breast Cancer Metastases.

Epithelial-mesenchymal transition (EMT) in cancer promotes metastasis and chemotherapy resistance. A subset of triple-negative breast cancer (TNBC) exhibits a mesenchymal gene signature that is associated with poor patient outcomes. We previously identified PTK6 tyrosine kinase as an oncogenic driver of EMT in a subset of TNBC. PTK6 induces EMT by stabilizing SNAIL, a key EMT-initiating transcriptional factor. Inhibition of PTK6 activity reverses mesenchymal features of TNBC cells and suppresses their metastases by promoting SNAIL degradation via a novel mechanism. In the current study, we identify membrane-associated RING-CH2 (MARCH2) as a novel PTK6-regulated E3 ligase that promotes the ubiquitination and degradation of SNAIL protein. The MARCH2 RING domain is critical for SNAIL ubiquitination and subsequent degradation. PTK6 inhibition promotes the interaction of MARCH2 with SNAIL. Overexpression of MARCH2 exhibits tumor suppressive properties and phenocopies the effects of SNAIL downregulation and PTK6 inhibition in TNBC cells, such as inhibition of migration, anoikis resistance, and metastasis. Consistent with this, higher levels of MARCH2 expression in breast and other cancers are associated with better prognosis. We have identified MARCH2 as a novel SNAIL E3 ligase that regulates EMT and metastases of mesenchymal TNBC. SIGNIFICANCE: EMT is a process directly linked to drug resistance and metastasis of cancer cells. We identified MARCH2 as a novel regulator of SNAIL, a key EMT driver, that promotes SNAIL ubiquitination and degradation in TNBC cells. MARCH2 is oncogene regulated and inhibits growth and metastasis of TNBC. These insights could contribute to novel strategies to therapeutically target TNBC.

Validation Study of the Newly Proposed Refined Diagnostic Criteria for Malignant Phyllodes Tumor With 136 Borderline and Malignant Phyllodes Tumor Cases.

The World Health Organization (WHO) diagnostic criteria for malignant phyllodes tumor (MPT) may miss a significant number of MPTs with metastatic potential. New refined diagnostic criteria (Refined Criteria) for MPT were recently proposed. The aim of this study is to validate the Refined Criteria. This validation study included 136 borderline (borderline phyllodes tumor [BoPT]) and MPT cases that were not included in the initial study. We evaluated tumor classifications based on both the Refined Criteria and the WHO criteria. The Refined Criteria defines MPT when these criteria are met (1) stromal overgrowth with ≥ 1 feature(s) of marked stromal cellularity, marked stromal cytologic atypia, or ≥10 mitoses per 10 high-power fields (10 mitoses/10 HPFs) or (2) marked stromal cellularity with ≥1 feature(s) of marked stromal cytologic atypia, ≥10 mitoses/10 HPFs or permeative border. The WHO criteria require all 5 morphologic features (stromal overgrowth, permeative border, marked stromal cellularity, marked stromal cytologic atypia, and ≥10 mitoses/10 HPFs) for an MPT diagnosis. Using the Refined Criteria, none of the 61 BoPTs developed metastasis and 40.0% of the 75 MPTs developed metastases; local recurrence was seen in 11.5% BoPTs and 25.3% MPTs. Using the WHO criteria, 9.6% of the 94 BoPTs developed metastases and 50.0% of the 42 MPTs developed metastases; 14.9% of the BoPTs had local recurrence and 28.6% of the MPTs had local recurrence. Nine (30.0%) of the 30 tumors that developed distant metastases were diagnosed as BoPTs by the WHO criteria. When we combined the 75 MPTs from this validation cohort with the 65 MPT cases from the published data using the Refined Criteria, 50 (35.7%) of the 140 MPTs developed metastases, whereas 8 cases with metastases were <5 cm. In the univariate analysis with log-rank test, stromal overgrowth, marked stromal cellularity, marked stromal cytologic atypia, ≥10 mitoses/10 HPFs, presence of heterologous components other than liposarcomatous component, and presence of stromal necrosis were significantly associated with the risk of metastasis (all with P < 0.05). In multivariate analysis with Cox proportional hazard regression, stromal overgrowth and marked stromal cellularity were significantly associated with metastasis (both with P < 0.001). The Refined Criteria are superior to the WHO criteria in predicting the clinical outcomes of BoPTs and MPTs. Using the Refined Criteria, 35.7% of 140 patients with MPT developed metastases, whereas none (0%) of the patients with BoPT developed metastases. Patients with MPT have a high metastatic rate; these patients may benefit from systemic chemotherapy or targeted therapies. In contrast, patients with BoPT may be managed with complete local excision alone without chemotherapy.

Distinct genomic and immunologic tumor evolution in germline TP53-driven breast cancers.

Pathogenic germline TP53 alterations cause Li-Fraumeni Syndrome (LFS), and breast cancer is the most common cancer in LFS females. We performed first of its kind multimodal analysis of LFS breast cancer (LFS-BC) compared to sporadic premenopausal BC. Nearly all LFS-BC underwent biallelic loss of TP53 with no recurrent oncogenic variants except ERBB2 (HER2) amplification. Compared to sporadic BC, in situ and invasive LFS-BC exhibited a high burden of short amplified aneuploid segments (SAAS). Pro-apoptotic p53 target genes BAX and TP53I3 failed to be up-regulated in LFS-BC as was seen in sporadic BC compared to normal breast tissue. LFS-BC had lower CD8+ T-cell infiltration compared to sporadic BC yet higher levels of proliferating cytotoxic T-cells. Within LFS-BC, progression from in situ to invasive BC was marked by an increase in chromosomal instability with a decrease in proliferating cytotoxic T-cells. Our study uncovers critical events in mutant p53-driven tumorigenesis in breast tissue.

Immature natural killer cells promote progression of triple-negative breast cancer.

Natural killer (NK) cells are cytotoxic lymphocytes that accumulate within the tumor microenvironment and are generally considered to be antitumorigenic. Using single-cell RNA sequencing and functional analysis of multiple triple-negative breast cancer (TNBC) and basal tumor samples, we observed a unique subcluster of Socs3highCD11b-CD27- immature NK cells that were present only in TNBC samples. These tumor-infiltrating NK cells expressed a reduced cytotoxic granzyme signature and, in mice, were responsible for activating cancer stem cells through Wnt signaling. NK cell-mediated activation of these cancer stem cells subsequently enhanced tumor progression in mice, whereas depletion of NK cells or Wnt ligand secretion from NK cells by LGK-974 decreased tumor progression. In addition, NK cell depletion or inhibition of their function improved anti-programmed cell death ligand 1 (PD-L1) antibody or chemotherapy response in mice with TNBC. Furthermore, tumor samples from patients with TNBC and non-TNBC revealed that increased numbers of CD56bright NK cells were present in TNBC tumors and were correlated to poor overall survival in patients with TNBC. Together, our findings identify a population of protumorigenic NK cells that may be exploited for both diagnostic and therapeutic strategies to improve outcomes for patients with TNBC.

Biallelic BRCA Loss and Homologous Recombination Deficiency in Nonbreast/Ovarian Tumors in Germline BRCA1/2 Carriers.

PURPOSE: Breast and ovarian tumors in germline BRCA1/2 carriers undergo allele-specific loss of heterozygosity, resulting in homologous recombination deficiency (HRD) and sensitivity to poly-ADP-ribose polymerase (PARP) inhibitors. This study investigated whether biallelic loss and HRD also occur in primary nonbreast/ovarian tumors that arise in germline BRCA1/2 carriers. METHODS: A clinically ascertained cohort of BRCA1/2 carriers with a primary nonbreast/ovarian cancer was identified, including canonical (prostate and pancreatic cancers) and noncanonical (all other) tumor types. Whole-exome sequencing or clinical sequencing results (n = 45) were analyzed. A pan-cancer analysis of nonbreast/ovarian primary tumors from germline BRCA1/2 carriers from The Cancer Genome Atlas (TCGA, n = 73) was used as a validation cohort. RESULTS: Ages of nonbreast/ovarian cancer diagnosis in germline BRCA1/2 carriers were similar to controls for the majority of cancer types. Nine of 45 (20%) primary nonbreast/ovarian tumors from germline BRCA1/2 carriers had biallelic loss of BRCA1/2 in the clinical cohort, and 23 of 73 (32%) in the TCGA cohort. In the combined cohort, 35% and 27% of primary canonical and noncanonical BRCA tumor types, respectively, had biallelic loss. High HRD scores (HRDex > 42) were detected in 81% of tumors with biallelic BRCA loss compared with 22% (P < .001) of tumors without biallelic BRCA loss. No differences in genomic profile, including mutational signatures, mutation spectrum, tumor mutational burden, or microsatellite instability, were found in primary nonbreast/ovarian tumors with or without biallelic BRCA1/2 loss. CONCLUSION: A proportion of noncanonical primary tumors have biallelic loss and evidence of HRD. Our data suggest that assessment of biallelic loss and HRD could supplement identification of germline BRCA1/2 mutations in selection of patients for platinum or PARP inhibitor therapy.

Subcategorization of T1 Bladder Cancer on Biopsy and Transurethral Resection Specimens for Predicting Progression.

CONTEXT.­: Despite continued surveillance and intravesical therapy, a significant subset of patients with lamina propria-invasive bladder cancer (T1) will progress to muscle-invasive disease or metastases. OBJECTIVE.­: To analyze the value of pathologic subcategorization of T1 disease in predicting progression. DESIGN.­: Six substaging methods were applied to a retrospective cohort of 73 patients, with pT1 urothelial carcinoma diagnosed on biopsy/transurethral resection. Additionally, the immunohistochemistry for GATA3 and cytokeratin 5/6 (CK5/6) was performed to study the prognostic value of stratifying T1 cancers into luminal or basal phenotypes. RESULTS.­: On follow-up (mean, 46 months), 21 patients (29%) experienced at least 1 recurrence without progression, and 16 (22%) had progression to muscle-invasive disease and/or distant metastasis. No differences were noted between progressors and nonprogressors with regard to sex, age, treatment status, medical history, tumor grade, and presence of carcinoma in situ. Substaging using depth of invasion (cutoff ≥1.4 mm), largest invasive focus (≥3.6 mm), aggregate linear length of invasion (≥8.9 mm), and number of invasive foci (≥3 foci) correlated significantly with progression and reduced progression-free survival, whereas invasion into muscularis mucosa or vascular plexus, or focal versus extensive invasion (focal when ≤2 foci, each <1 mm) failed. Patients with luminal tumors had higher incidence of progression than those with nonluminal tumors (27% versus 11%), although the difference was statistically insignificant (P = .14). CONCLUSIONS.­: Substaging of T1 bladder cancers should be attempted in pathology reports. Quantifying the number of invasive foci (≥3) and/or measuring the largest contiguous focus of invasive carcinoma (≥3.6 mm) are practical tools for prognostic substaging of T1 cancers.

Renal Oncocytoma With Both Lymphovascular Invasion and Prominent Intracytoplasmic Vacuole-Like Spaces: A Case Report and Review of the Literature.

Here we report a case of renal oncocytoma in a 68 year-old male. The diagnosis was initially made on a needle biopsy 6 years prior to the partial nephrectomy. The case is unique that in addition to the gross and microscopic features commonly seen in renal oncocytomas, both lymphovascular invasion and prominent intracytoplasmic vacuole-like spaces are also present in this tumor. Although vascular invasion is increasingly recognized as compatible with renal oncocytoma, intracytoplasmic vacuoles are a rare and unusual finding that may lead to diagnostic difficulty. The diagnosis of renal oncocytoma was confirmed after immunohistochemistry was performed to argue against succinate dehydrogenase deficient renal cell carcinoma (RCC) and chromophobe RCC. This case highlights the importance for practicing pathologists to recognize the rare co-occurrence of lymphovascular invasion and large intracytoplasmic vacuole-like spaces in renal oncocytoma. Other differential diagnoses may include emerging renal tumor entities, such as the recently-proposed eosinophilic vacuolated tumor.