The POWER-PAK Score Characterizes Tumor Response to 3 Months of Preoperative Endocrine Therapy.

BACKGROUND: The Pre-Operative Window of Endocrine Therapy to Inform Radiation Therapy Decisions (POWER, NCT04272801) trial aims to determine whether 3 months of preoperative endocrine therapy (pre-ET) informs adjuvant radiation therapy decisions among older women with early stage, ER-positive breast cancer. We propose the POWER Pathologic Assessment and Ki-67 (POWER-PAK) scoring system to characterize the histologic effects of pre-ET. METHODS: Histologic evaluation was performed on core biopsy and lumpectomy specimens from 37 POWER trial participants who completed pre-ET and surgery. The POWER-PAK score consists of tumor regression, decrease in Ki-67 expression, and ER expression, each ranging from 0 to 2. Scores were aggregated to create the POWER-PAK score with a range from 0 to 6. Participants with no residual tumor were labelled 6-NRT. RESULTS: ER expression did not decrease after pre-ET. Ki-67 decreased from 13% in biopsy specimens to 5% in the lumpectomy specimens (p < 0.001). Cellularity decreased from 40% to 23% (p < 0.001). There was heterogeneity of POWER-PAK scores ranging from 2 to 6-NRT: score of 2, n = 2 (5.4%); 4, n = 8 (21.6%); 5, n = 4 (10.8%); 6, n = 16 (43.2%); and 6-NRT, n = 7 (18.9%). Participants with a score ≥ 5 were more likely to have smaller tumors after pre-ET compared with those with a score < 5 (p = 0.04). CONCLUSIONS: The tumor responses following treatment with pre-ET are heterogenous. We propose that the POWER-PAK scoring system can be used to quantify response to pre-ET. Future studies will explore the use of POWER-PAK to support informed decision-making for adjuvant therapy options for older women with early stage breast cancer.

GATA3 Expression in Common Gynecologic Carcinomas: A Potential Pitfall.

GATA binding protein 3 (GATA3) immunohistochemistry is primarily used as a marker of breast and urothelial differentiation, particularly in metastatic settings. In the gynecologic tract it also serves a robust marker for mesonephric and trophoblastic tumors. However, expression has also been described in more common malignancies of gynecologic tract including ovarian, endometrial, and cervical carcinomas. Data on the distribution of GATA3 expression in gynecologic malignancies is somewhat limited, particularly across different histologic subtypes of ovarian, endometrial, and cervical carcinomas. To assess the rates of GATA3 expression among common gynecologic cancers of various histologic types, 100 ovarian carcinomas, 64 endometrial carcinomas/atypical hyperplasias, 16 cervical squamous cell carcinomas (SCCs), and 14 endocervical adenocarcinomas were evaluated by immunohistochemistry for GATA3 positivity. Eight percent of endometrial carcinomas expressed GATA3, including 2 serous carcinomas, 1 carcinosarcoma, and 1 case of atypical hyperplasia. Six percent of ovarian carcinomas were GATA3-positive including 2 clear cell carcinomas, 2 mucinous adenocarcinomas, and 2 high-grade serous carcinomas. Thirty-eight percent of cervical SCCs showed weak to moderate staining in up to 50% of tumor cells. All endocervical adenocarcinomas were entirely negative for GATA3. In summary, GATA3 shows focal weak to moderate expression in a subset of endometrial and ovarian carcinomas. In contrast, usual-type endocervical adenocarcinomas are typically negative for GATA3, which can be helpful in differentiating them from mesonephric proliferations or carcinomas. A larger proportion of cervical SCCs express GATA3, therefore caution should be exercised when using this stain in the setting of a lower genitourinary carcinomas.

Effect of a tissue selective estrogen complex on breast cancer: Role of unique properties of conjugated equine estrogen.

The Women's Health Initiative studies reported that the menopausal hormone therapy (MHT) regimen containing conjugated equine estrogen (CEE) and medroxyprogesterone acetate increased, whereas CEE alone reduced breast cancer incidence. These observations suggest the possibility that CEE might exert unique actions on breast and also suggest the need to eliminate the progestogen from MHT regimens. A MHT regimen called a tissue selective estrogen complex (TSEC), containing CEE plus bazedoxifene (BZA), to avoid the need for a progestogen, was developed and FDA approved. Our study addressed two questions regarding this TSEC: (i) whether CEE exert effects on breast cancer which differ from those of estradiol (E2 ) and (ii) whether BZA antagonize the effects of E2 and CEE on breast cancer? Two rodent models (NMU and ACI) were used to compare the effect of CEE with E2 on mammary tumor formation, proliferation and apoptosis. In both the NMU and ACI models, E2 significantly increased tumor incidence and multiplicity whereas in striking contrast CEE did not, even though the estrogenic effects of CEE and E2 on uterine weight were identical. Mechanistically E2 blocked whereas CEE stimulated apoptosis (cleaved caspase-3) in ACI animals and only E2 stimulated proliferation (Ki67). BZA exerted highly potent anti-estrogenic effects on tumors by completely blocking palpable tumor formation. These data suggest that the CEE/BZA TSEC may be a safer, breast-antagonistic, MHT agent for women and might have potential to prevent breast cancer while relieving menopausal symptoms.

Mesothelium expression of vascular cell adhesion molecule-1 (VCAM-1) is associated with an unfavorable prognosis in epithelial ovarian cancer (EOC).

BACKGROUND: Mesothelium vascular cell adhesion molecule-1 (VCAM-1) expression in the metastatic epithelial ovarian cancer (EOC) microenvironment is induced by tumor and mediates tumor cell invasion. VCAM-1 imaging suggests expression during treatment is an indicator of platinum resistance. Here, we assess the potential prognostic significance of mesothelium VCAM-1 expression and prospectively evaluate whether soluble VCAM-1 (sVCAM-1) is a surrogate for mesothelium expression. METHODS: A retrospective review of EOC patients was performed to evaluate outcomes with mesothelium VCAM-1 expression determined by immunohistochemistry of peritoneum or omentum specimens. A prospective cohort of EOC patients was identified and followed through primary treatment. Serum for sVCAM-1 evaluation, which was performed via enzyme-linked immunosorbent assay, was collected before surgery or neoadjuvant chemotherapy and at each treatment cycle. Peritoneal specimens were obtained during debulking to assess mesothelial VCAM-1 expression. RESULTS: A retrospective review identified 54 advanced-stage EOC patients. Patients expressing mesothelium VCAM-1 had shortened overall survival (44 vs 79 months, P = 0.035) and progression-free survival (18 vs 67 months, P = 0.010); the median time to platinum resistance was 36 months for VCAM-1-expressing patients and not yet determined for the VCAM-1-negative group. In our prospective observational cohort, 18 EOC patients completed primary treatment; 3 were negative for mesothelium VCAM-1 expression, and sVCAM-1 did not vary between groups. CONCLUSIONS: Mesothelium VCAM-1 expression is negatively associated with progression-free and overall survival in EOC. This is especially compelling in light of previous data suggesting that persistent VCAM-1 expression during treatment is an indicator of platinum resistance. Our pilot study had insufficient cases to determine whether sVCAM-1 would substitute for mesothelium expression. Cancer 2017;123:977-84. © 2016 American Cancer Society.

Mismatch repair status and PD-L1 expression in clear cell carcinomas of the ovary and endometrium.

Clear cell carcinoma represents a distinct histologic type of müllerian carcinoma that is resistant to conventional chemotherapy. Expression of programmed cell death ligand (PD-L1) has been associated with immune evasion in numerous tumor types and may be used to identify patients who will benefit from targeted immunotherapy, particularly in the setting of mismatch repair defects. We evaluated PD-L1 expression in 23 ovarian clear cell carcinomas and 21 endometrial clear cell carcinomas, and correlated expression with mismatch repair status. Tumor PD-L1 staining was seen in 43% of ovarian tumors and 76% of endometrial tumors, including 71% of cases (67% of ovarian and 75% of endometrial) with mismatch repair defects. Extensive tumoral staining (>50%) was seen in only one case (an endometrial case with MSH6 loss). However, tumoral PD-L1 expression remained common in mismatch repair-intact tumors and mismatch repair status was not significantly correlated with PD-L1 expression. The increased incidence of PD-L1 positivity in tumor cells (P=0.04) in endometrial vs ovarian clear cell carcinomas suggests differences in the tumor microenvironment of these histologically and molecularly similar tumors that may inform treatment options. These results suggest that clear cell histology may be a useful susceptibility marker for immunotherapy targeting the PD-1/PD-L1 axis irrespective of mismatch repair status, particularly in endometrial carcinomas.

Lobular Breast Cancer and Abdominal Metastases: A Retrospective Review and Impact on Survival.

BACKGROUND: The predominant breast cancer subtypes, invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC), have similar recurrence and survival rates but differing patterns of metastatic recurrence. METHODS: A retrospective review of breast cancers treated at an academic medical center from 1999 to 2012 was performed. Demographic, pathologic, treatment, and follow-up data were collected for 179 ILC and 358 IDC patients (1:2 stage-matched). The median follow-up was 4.7 years. RESULTS: The baseline characteristics were similar in the two groups. ILC was more likely to be hormone-receptor-positive/HER2-negative and mammographically occult. The number of surgical resections, breast conservation rate, systemic treatment, and taxane use was similar between the groups. The overall recurrence rate was the same. ILC recurred more often in the abdominal cavity (24.3% in ILC vs. 4.1% in IDC, p = 0.001). The disease-free survival and overall survival were equal. On multivariate analysis, age, stage of disease, hormone receptor status, and systemic therapy were associated with survival, but histology was not. CONCLUSIONS: Compared to ductal breast cancers, lobular breast cancers recur more often in the abdominal cavity. Both ILC and IDC have comparable surgical and medical treatment outcomes and survival. Our data suggest that enhanced surveillance and imaging might be useful in ILC.

Clinical Significance of Positive Pelvic Washings in Uterine Papillary Serous Carcinoma Confined to an Endometrial Polyp.

Uterine papillary serous carcinoma (UPSC) represents 10% of endometrial carcinomas. Significant number of patients initially present with extrauterine disease. The role of adjuvant treatment in low stage, especially polyp-confined UPSC is controversial. This multi-institutional study evaluated the significance of positive pelvic washing (PW) and adjuvant treatment on disease recurrence in a setting of endometrial polyp-confined UPSC. Surgical pathology files from 3 institutions were searched for cases of endometrial polyp-confined UPSC. Following histologic review, cases were clinically staged as Stage I, without myoinvasion or lymphovascular invasion. Clinicopathologic characteristics, results of PW, and type of adjuvant therapy were recorded. Statistical analysis using the Kaplan-Meier method for survival and Fisher exact test were performed. Thirty-three patients were included in the study. All patients were diagnosed with polyp-confined UPSC. The size of the polyp ranged from 0.3 to 4.3 cm. PW was positive for tumor cells in 8/33 (24%) patients. Twenty-two patients (66.6%) received some type of adjuvant treatment. Six patients (18%) developed recurrent disease. There was no significant difference in disease-free survival in the patients receiving adjuvant treatment versus not (P=0.375). However, there was significant association (P=0.0013) between positive PW and disease recurrence. Data are conflicting whether positive PW affects prognosis in low-stage endometrial carcinomas. Our study showed that in UPSC, malignant cells can be present in PW without lymphovascular invasion or myoinvasion and may have negative prognostic implication. Our data also reflect the controversies in the role of adjuvant treatment in endometrium-confined UPSC.

Women at extreme risk for obesity-related carcinogenesis: Baseline endometrial pathology and impact of bariatric surgery on weight, metabolic profiles and quality of life.

OBJECTIVES: The study objectives were to determine baseline endometrial histology in morbidly obese women undergoing bariatric surgery and to assess the surgical intervention's impact on serum metabolic parameters, quality of life (QOL), and weight. METHODS: Women undergoing bariatric surgery were enrolled. Demographic and clinicopathologic data, serum, and endometrium (if no prior hysterectomy) were collected preoperatively and serum collected postoperatively. Serum global biochemical data were assessed pre/postoperatively. Welch's two sample t-tests and paired t-tests were used to identify significant differences. RESULTS: Mean age of the 71 women enrolled was 44.2 years, mean body mass index (BMI) was 50.9 kg/m(2), and mean weight loss was 45.7 kg. Endometrial biopsy results: proliferative (13/30; 43%), insufficient (8/30; 27%), secretory (6/30; 20%) and hyperplasia (3/30; 10%-1 complex atypical, 2 simple). QOL data showed significant improvement in physical component scores (PCS means 33.9 vs. 47.2 before/after surgery; p<0.001). Twenty women underwent metabolic analysis which demonstrated significantly improved glucose homeostasis, improved insulin responsiveness, and free fatty acid levels. Significant perturbations in tryptophan, phenylalanine and heme metabolism suggested decreased inflammation and alterations in the intestinal microbiome. Most steroid hormones were not significantly impacted with the exception of decreased DHEAS and 4-androsten metabolites. CONCLUSIONS: Bariatric surgery is accompanied by an improved physical quality of life as well as beneficial changes in glucose homeostasis, insulin responsiveness, and inflammation to a greater extent than the hormonal milieu. The potential cancer protective effects of bariatric surgery may be due to other mechanisms other than simply hormonal changes.

VCAM-1 on peritoneum and α4ß1 integrin in endometrium and their implications in endometriosis.

The objective of the study is to investigate vascular cellular adhesion molecule-1 (VCAM-1) expression on peritoneal mesothelial cells and α4ß1 integrin on eutopic endometrium as possible mechanisms in the pathogenesis of endometriosis. It is a case-control study carried out at an academic medical center. Participants are patients with (n=9) and without (n=15) endometriosis. The main outcome measures included VCAM-1 expression on peritoneal mesothelial cells and α4ß1 expression on eutopic endometrium using immunohistochemistry and flow cytometry, respectively. Patients with endometriosis were more likely to express VCAM-1 on peritoneal mesothelial cells, both in areas with and without macroscopic disease, compared with patients without endometriosis (9/9 vs. 3/15, P<0.001). No differences were found between cases and controls in regards to eutopic endometrial expression of α4ß1 integrin. The presence of VCAM-1 on peritoneal mesothelial cells is associated with endometriosis. This field effect, in addition to the similarity found with regards to the expression of α4ß1 integrin in eutopic endometrium between cases and controls, may implicate the expression of VCAM-1 in the peritoneum, and not changes in the eutopic endometrium, as a contributor to the pathogenesis of endometriosis.

Inhibition of α4ß1 integrin increases ovarian cancer response to carboplatin.

OBJECTIVE: The inability to successfully treat women with ovarian cancer is due to the presence of metastatic disease at diagnosis and the development of platinum resistance. Ovarian cancer metastasizes throughout the peritoneal cavity by attaching to and invading through the mesothelium lining the peritoneum using a mechanism that involves α4ß1 integrin and its ligand (vascular cell adhesion molecule) VCAM-1. Integrin α4ß1 expression on tumor cells is known to confer protection from therapy in other cancers, notably multiple myeloma. We evaluated the role of α4ß1 integrin in response to platinum-based therapy in a mouse model of peritoneal ovarian cancer metastasis by treatment with a humanized anti-α4ß1 integrin function-blocking antibody. METHODS: Integrin α4ß1 expression on primary human ovarian cancer cells, fallopian tube and ovarian surface epithelia and fresh tumor was assessed by flow-cytometry. The therapeutic impact of anti-α4ß1 treatment was assessed in murine models of platinum-resistant peritoneal disease and in vitro using the platinum resistant ovarian cancer cell lines. RESULTS: Treatment of tumor-bearing mice with human-specific α4ß1 integrin function-blocking antibodies, anti-VCAM-1 antibody or carboplatin alone had no effect on tumor burden compared to the IgG control group. However, the combined treatment of anti-α4ß1 integrin or anti-VCAM-1 with carboplatin significantly reduced tumor burden. In vitro, the combination of carboplatin and anti-α4ß1 integrin antibodies resulted in increased cell death and doubling time. CONCLUSIONS: Our findings support a role for α4ß1 integrin in regulating treatment response to carboplatin, implicating α4ß1 integrin as a potential therapeutic target to influence platinum responsiveness in otherwise resistant disease.

Yolk Sac Differentiation in Endometrial Carcinoma: Incidence and Clinicopathologic Features of Somatically Derived Yolk Sac Tumors Versus Carcinomas With Nonspecific Immunoexpression of Yolk Sac Markers.

Endometrial somatically derived yolk sac tumors are characterized by yolk sac morphology with AFP, SALL-4, and/or Glypican-3 immunoexpression. Yolk sac marker expression, however, is not limited to tumors with overt yolk sac histology. Three hundred consecutive endometrial malignancies were assessed for immunomarkers of yolk sac differentiation. Of these, 9% expressed ≥1 yolk sac marker, including 29% of high-grade tumors. Only 3 (1%) met morphologic criteria for yolk sac differentiation; these were originally diagnosed as serous, high-grade NOS, and dedifferentiated carcinoma. Two were MMR-intact and comprised exclusively of yolk sac elements, while the dedifferentiated case was MMR deficient and had a background low-grade endometrioid carcinoma; this case also showed BRG1 loss. All 3 were INI1 intact. Nonspecific yolk sac marker expression was seen in 14 carcinosarcomas, 4 endometrioid, 2 serous, 1 clear cell, 1 dedifferentiated, 1 mixed serous/clear cell, and 1 mesonephric-like carcinoma. INI1 was intact in all cases; one showed BRG1 loss. Twenty were MMR-intact, and 4 were MMR deficient. All MMR-deficient cases with yolk sac marker expression, both with and without true yolk sac morphology, had no evidence of residual disease on follow-up, whereas 82% of MMR-intact cases developed recurrent/metastatic disease. In summary, endometrial somatically derived yolk sac tumors were rare but under-recognized. While AFP immunostaining was specific for this diagnosis, Glypican-3 and SALL-4 expression was seen in a variety of other high-grade carcinomas. INI1 loss was not associated with yolk sac morphology or immunomarker expression in the endometrium, and BRG1 loss was rare. All patients with MMR-deficient carcinomas with yolk sac immunoexpression +/- morphology were disease-free on follow-up, whereas the majority of MMR-intact cancers showed aggressive disease.

Patient-derived response estimates from zero-passage organoids of luminal breast cancer.

Background: Primary luminal breast cancer cells lose their identity rapidly in standard tissue culture, which is problematic for testing hormone interventions and molecular pathways specific to the luminal subtype. Breast cancer organoids are thought to retain tumor characteristics better, but long-term viability of luminal-subtype cases is a persistent challenge. Our goal was to adapt short-term organoids of luminal breast cancer for parallel testing of genetic and pharmacologic perturbations. Methods: We freshly isolated patient-derived cells from luminal tumor scrapes, miniaturized the organoid format into 5 µl replicates for increased throughput, and set an endpoint of 14 days to minimize drift. Therapeutic hormone targeting was mimicked in these "zero-passage" organoids by withdrawing ß-estradiol and adding 4-hydroxytamoxifen. We also examined sulforaphane as an electrophilic stress and commercial neutraceutical with reported anti-cancer properties. Downstream mechanisms were tested genetically by lentiviral transduction of two complementary sgRNAs and Cas9 stabilization for the first week of organoid culture. Transcriptional changes were measured by RT-qPCR or RNA sequencing, and organoid phenotypes were quantified by serial brightfield imaging, digital image segmentation, and regression modeling of cellular doubling times. Results: We achieved >50% success in initiating luminal breast cancer organoids from tumor scrapes and maintaining them to the 14-day zero-passage endpoint. Success was mostly independent of clinical parameters, supporting general applicability of the approach. Abundance of ESR1 and PGR in zero-passage organoids consistently remained within the range of patient variability at the endpoint. However, responsiveness to hormone withdrawal and blockade was highly variable among luminal breast cancer cases tested. Combining sulforaphane with knockout of NQO1 (a phase II antioxidant response gene and downstream effector of sulforaphane) also yielded a breadth of organoid growth phenotypes, including growth inhibition with sulforaphane, growth promotion with NQO1 knockout, and growth antagonism when combined. Conclusions: Zero-passage organoids are a rapid and scalable way to interrogate properties of luminal breast cancer cells from patient-derived material. This includes testing drug mechanisms of action in different clinical cohorts. A future goal is to relate inter-patient variability of zero-passage organoids to long-term outcomes.

Atypical lobular hyperplasia and lobular carcinoma in situ at core breast biopsy: use of careful radiologic-pathologic correlation to recommend excision or observation.

PURPOSE: To assess the utility of precise radiologic and pathologic correlation for establishing imaging-histologic concordance or discordance as a method to limit the number of patients requiring surgical excision when atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS) is diagnosed at core biopsy. MATERIALS AND METHODS: This study was approved by the institutional review board, and the requirement to obtain informed consent was waived. The pathology database was searched from 2000 to 2010 for core biopsies yielding ALH or LCIS devoid of any additional lesion that independently necessitated excision. All cases had to have either subsequent surgical excision or a minimum of 2 years of imaging follow-up. This yielded 50 cases from 49 women aged 40-73 years (mean age, 59 years). The authors performed detailed radiologic-pathologic analysis while blinded to subsequent follow-up information, comparing all biopsy-related images with the histologic findings at core biopsy and then designating each core biopsy finding as concordant or discordant. Then, results of subsequent surgery or extended follow-up for each case were unblinded and compared with original concordant or discordant designations. Outcomes and confidence intervals (CIs) were calculated. RESULTS: Of the 43 benign concordant core biopsy findings, none were upgraded at surgery (n = 38) or extended follow-up (n = 5) (95% CI: 0%, 8%). Of the seven discordant biopsy findings, two were upgraded to ductal carcinoma in situ at surgery (n = 5); none of the cases were upgraded at follow-up (n = 2). CONCLUSION: When careful radiologic-pathologic correlation is performed and concordance is achieved, women with ALH or LCIS at core biopsy can be observed.

Interactive case review of radiologic and pathologic findings from breast biopsy: are they concordant? How do I manage the results?

The number of imaging-guided percutaneous breast biopsies performed has steadily increased as imaging techniques have improved. Percutaneous biopsy is becoming more commonplace and supplanting excisional biopsy as the preferred diagnostic tool. The radiologist's role in caring for patients who undergo breast biopsy extends beyond imaging to identifying lesions for biopsy and then performing the procedure. Radiologists must also be cognizant of radiologic-pathologic correlation to determine whether biopsy results are concordant with imaging findings and make management recommendations. Management of microcalcifications, masses, and areas of asymmetry begins with recognizing and characterizing the findings with the proper Breast Imaging Reporting and Data System (BI-RADS) lexicon. Determining concordance between imaging findings and histologic results is equally important. The decision to recommend surgical excision or short-term follow-up relies heavily on whether the histologic diagnosis correlates with the imaging findings, a determination that is part of the radiologist's responsibilities if he or she performs the biopsy. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.334125123/-/DC1.

Women 50 years or younger with endometrial cancer: the argument for universal mismatch repair screening and potential for targeted therapeutics.

OBJECTIVE: To identify young patients with endometrial cancer with potential Lynch-related DNA mismatch repair (MMR) protein expression defects and stathmin (STMN1) expression (part of the phosphoinositol 3-kinase pathway) and to correlate clinical data. METHODS: This retrospective study included women with endometrial cancer who were 50 years or younger at diagnosis. Clinical data were abstracted from chart review. Immunohistochemistry for MMR protein expression, STMN1, and pSTMN1 was performed and univariate analyses performed. RESULTS: The mean age of 111 patients was 43 years, and the mean body mass index was 39.6 kg/m². The majority of the endometrial cancers were endometrioid histology (87.4%), International Federation of Gynecology and Obstetrics stage I (73%) and grade 1 (58.6%). Loss of at least one MMR protein on immunohistochemistry was identified in 26% to 41% of patients depending on stringency. Women with loss of MMR protein expression were compared to women with intact tumor protein expression and were less likely to be stage I (58.6% vs 78.0%; P = 0.043), more likely to have grade 3 tumors (32.1% vs 13.9%; P = 0.034), had larger tumors (6.2 vs 3.7 cm; P < 0.001), had positive lymph nodes more often (24.1% vs 3.7%; P < 0.001), and more often reported a first-degree relative with colon cancer (17.2% vs 1.2%; P < 0.001). There were no significant differences in age, weight, body mass index, medical comorbidities, recurrence, or survival. Women with high STMN1 staining had significantly more grade 3 tumors (56.3% vs 15.8%; P = 0.001), more stage III/IV disease (37.5% vs 15.8%; P = 0.04), had higher mean percentage of myometrial invasion (38.9% vs 16.7%; P = 0.003), and more lymphovascular space invasion (43.8% vs 13.7%; P = 0.004). CONCLUSIONS: Clinical factors failed to differentiate between patients with intact or missing MMR protein expression, which supports universal screening for Lynch-associated protein defects in young women with endometrial cancer. Additionally, STMN1 staining may identify more aggressive tumors, which might benefit from more aggressive treatments or targeted treatment options.

A genetic mosaic mouse model illuminates the pre-malignant progression of basal-like breast cancer.

Basal-like breast cancer is an aggressive breast cancer subtype, often characterized by a deficiency in BRCA1 function and concomitant loss of p53 . While conventional mouse models enable the investigation of its malignant stages, one that reveals its initiation and pre-malignant progression is lacking. Here, we leveraged a mouse genetic system known as M osaic A nalysis with D ouble M arkers (MADM) to generate rare GFP-labeled Brca1 , p53 -deficient cells alongside RFP+ wildtype sibling cells in the mammary gland. The mosaicism resembles the sporadic initiation of human cancer and enables spatially resolved analysis of mutant cells in comparison to paired wildtype sibling cells. Mammary tumors arising in the model show transcriptomic and genomic characteristics similar to human basal-like breast cancer. Analysis of GFP+ mutant cells at interval time points before malignancy revealed a stepwise progression of lesions from focal expansion to hyper-alveolarization and then to micro-invasion. These stereotyped morphologies indicate the pre-malignant stage irrespective of the time point at which it is observed. Paired analysis of GFP-RFP siblings during focal expansion suggested that hyper-alveolarized structures originate from ductal rather than alveolar cells, despite their morphological similarities to alveoli. Evidence for luminal-to-basal transition at the pre-malignant stages was restricted to cells that had escaped hyper-alveoli and progressed to micro-invasive lesions. Our MADM-based mouse model presents a useful tool for studying the pre-malignancy of basal-like breast cancer. Summary statement: A mouse model recapitulates the process of human basal-like breast tumorigenesis initiated from sporadic Brca1, p53 -deficient cells, empowering spatially-resolved analysis of mutant cells during pre-malignant progression.

A genetic mosaic mouse model illuminates the pre-malignant progression of basal-like breast cancer.

Basal-like breast cancer (BLBC) is highly aggressive, and often characterized by BRCA1 and p53 deficiency. Although conventional mouse models enabled the investigation of BLBC at malignant stages, its initiation and pre-malignant progression remain understudied. Here, we leveraged a mouse genetic system known as mosaic analysis with double markers (MADM) to study BLBC initiation by generating rare GFP+Brca1, p53-deficient mammary cells alongside RFP+ wild-type sibling cells. After confirming the close resemblance of mammary tumors arising in this model to human BLBC at both transcriptomic and genomic levels, we focused our studies on the pre-malignant progression of BLBC. Initiated GFP+ mutant cells showed a stepwise pre-malignant progression trajectory from focal expansion to hyper-alveolarization and then to micro-invasion. Furthermore, despite morphological similarities to alveoli, hyper-alveolarized structures actually originate from ductal cells based on twin-spot analysis of GFP-RFP sibling cells. Finally, luminal-to-basal transition occurred exclusively in cells that have progressed to micro-invasive lesions. Our MADM model provides excellent spatiotemporal resolution to illuminate the pre-malignant progression of BLBC, and should enable future studies on early detection and prevention for this cancer.

Dichotomous ovarian cancer-initiating potential of Pax8+ cells revealed by a mouse genetic mosaic model.

Different cellular compartments within a tissue present distinct cancer-initiating capacities. Current approaches to dissect such heterogeneity require cell-type-specific genetic tools based on a well-understood lineage hierarchy, which are lacking for many tissues. Here, we circumvented this hurdle and revealed the dichotomous capacity of fallopian tube Pax8+ cells in initiating ovarian cancer, utilizing a mouse genetic system that stochastically generates rare GFP-labeled mutant cells. Through clonal analysis and spatial profiling, we determined that only clones founded by rare, stem/progenitor-like Pax8+ cells can expand on acquiring oncogenic mutations whereas vast majority of clones stall immediately. Furthermore, expanded mutant clones undergo further attrition: many turn quiescent shortly after the initial expansion, whereas others sustain proliferation and manifest a bias toward Pax8+ fate, underlying early pathogenesis. Our study showcases the power of genetic mosaic system-based clonal analysis for revealing cellular heterogeneity of cancer-initiating capacity in tissues with limited prior knowledge of lineage hierarchy.

Magnetic resonance imaging appearance of scurvy with gelatinous bone marrow transformation.

Scurvy is a lethal but treatable disease that is rare in industrialized countries. Caused by vitamin C deficiency, it is most prevalent in persons of low socioeconomic status and smokers. Low levels of circulating vitamin C result in poor collagen fiber formation that, in turn, leads to demineralized bones, microfractures, and poor healing. Here we report a case of scurvy in a 5-year-old boy with normal radiographs in whom initial concern for leukemia based upon magnetic resonance imaging and clinical presentation led to a bone marrow biopsy revealing gelatinous transformation.

Tetra-methoxystilbene modulates ductal growth of the developing murine mammary gland.

Extensive data suggest that estradiol contributes to the development of breast cancer by acting as a mitogen and exerting direct genotoxic effects after enzymatic conversion to 4-hydroxyestradiol (4-OHE2) via cytochrome P450 1B1 (CYP1B1). The mammary gland, ovary, and uterus all express CYP1B1. Overexpression of this enzyme has been associated with an increased risk of breast cancer and blockade might reduce this carcinogenic effect. For this reason, we conducted systematic in vitro and in vivo studies of a CYP1B1 inhibitor, TMS (2,3',4,5'-tetramethoxystilbene). We found that TMS blocked the enzymatic conversion of radiolabeled estradiol to both 2-hydroxyestradiol (2-OHE2) and 4-OHE2, but did not inhibit Cyp1b1 message formation. In vivo studies using mass spectrometry showed that TMS inhibited formation of 2-OHE2 and 4-OHE2 and the resulting estrogen-DNA adducts. To examine its biologic actions in vivo, we investigated whether TMS could block the hyperplastic changes that occur in the developing breast of aromatase-transfected mice. We found that TMS induced a significant reduction of ductal structures in mice less than 6 months in age. In older mice, no reduction in breast morphology occurred. These latter studies uncovered unexpected estrogen agonistic actions of TMS at high doses, including a paradoxical stimulation of breast ductal structures and the endometrium. These studies suggest that the enzyme inhibitory properties of TMS, as well as the effects on developing breast, could implicate a role for TMS in breast cancer prevention, but only in low doses and on developing breast.