Kristen A. Atkins

Using Biomarkers as Objective Standards in the Diagnosis of Cervical Biopsies

Histopathologic diagnosis of cervical biopsies determines clinical management of patients with an abnormal cervical cancer-screening test yet is prone to poor interobserver reproducibility. Immunohistochemical staining for biomarkers related to the different stages of cervical carcinogenesis may provide objective standards to reduce diagnostic variability of cervical biopsy evaluations but systematic, rigorous evaluations of their potential clinical utility are lacking. To address diagnostic utility of human papillomavirus (HPV) L1, p16INK4a, and Ki-67 immunohistochemical staining for improving diagnostic accuracy, we conducted a community-based and population-based evaluation using 1455 consecutive cervical biopsies submitted to the Department of Pathology at the University of Virginia during a period of 14 months. Thin-sections of each biopsy from 1451 of 1455 (99.7%) biopsies underwent evaluation of immunohistochemical stains for the 3 biomarkers, masked to the original diagnosis, and the results were compared with an adjudicated, consensus diagnosis by 3 pathologists. p16INK4a immunostaining, using the strongest staining as the cutpoint, was 86.7% sensitive and 82.8% specific for cervical intraepithelial neoplasia (CIN) grade 2 or more severe (CIN2+) diagnoses. The performance of p16INK4a was more sensitive (P<0.001), less specific (P<0.001), and of similar overall accuracy for CIN2+ compared with the combined performance of all pathologist reviews in routine clinical diagnostic service (sensitivity=68.9%, specificity=97.2%). Ki-67 immunostaining was also strongly associated with a CIN2+ diagnosis but its performance at all staining intensities was inferior to p16INK4a immunostaining, and did not increase the accuracy of CIN2+ diagnosis when combined with p16INK4a immunostaining compared with p16INK4a immunostaining alone. We found no utility for L1 immunostaining in distinguishing between CIN and non-CIN. In conclusion, with a rigorous evaluation, we found immunohistochemical staining for p16INK4a to be a useful and reliable diagnostic adjunct for distinguishing biopsies with and without CIN2+.

Vascular Cell Adhesion Molecule-1 Is a Regulator of Ovarian Cancer Peritoneal Metastasis

Ovarian cancers metastasize by attaching to and invading through the mesothelium, a single layer of mesothelial cells lining the peritoneal cavity. The presence of invasive peritoneal metastases is associated with a poor prognosis for ovarian cancer (5-year survival <25%). Vascular cell adhesion molecule-1 (VCAM-1) is a cell surface receptor that mediates leukocyte attachment and extravasation across endothelial and mesothelial monolayers at sites of inflammation. Membranous VCAM-1 expression was observed on the mesothelium of 13 of 14 women with ovarian cancer compared with 6 of 15 who were cancer-free. Using a cell culture model system of mesothelial invasion, highly tumorigenic SKOV-3 and ES-2 cells were 2.5 to 3 times more efficient in transmigration through the mesothelial monolayer compared with poorly tumorigenic OVCAR-3 cells. Blocking antibodies to, or small interfering RNA knockdown of, VCAM-1 or its ligand alpha(4)beta(1) integrin significantly decreased, but did not completely inhibit, transmigration of SKOV-3 cells through mesothelial monolayers. Furthermore, using a mouse model of ovarian cancer metastasis, treatment with VCAM-1 function-blocking antibodies decreased tumor burden and increased survival. Together, these observations implicate VCAM-1-alpha(4)beta(1) integrin interactions in the regulation of ovarian cancer cell mesothelial invasion and metastatic progression and offer the possibility of novel therapeutic targets.

The Use of p16 in enhancing the histologic classification of uterine smooth muscle tumors.

Background Uterine smooth muscle tumors can usually be divided histologically into leiomyoma (L) and leiomyosarcoma (LMS). Occasionally, the histologic features are indeterminate and classified as smooth muscle tumor of uncertain malignant potential (STUMP). Recent gene expression studies have found p16 overexpressed in LMS when compared with normal myometrium. This study evaluated the protein expression of p16 by immunohistochemistry in LMS, L, and normal myometrium. Additionally, 8 tumors originally classified as STUMP were evaluated for p16 expression and correlated to their clinical outcome. Methods A tissue microarray was constructed and composed of 15 LMS, 8 STUMPs, 22 L, and 10 samples of normal myometrium. p16 expression was correlated with clinical outcome and histologic features. Results Twelve of the 15 LMS strongly and diffusely expressed p16, 3 of the L had focal p16 staining, and none of the normal myometria were p16 positive. Three of the tumors originally classified as STUMP developed metastatic disease and 2 of these tumors had strong, diffuse p16 positivity. Histologically, these 2 cases were characterized by coagulative tumor cell necrosis and only mild cytologic atypia. Conclusions p16 is preferentially expressed in LMS with only rare L showing positivity. Histologically, tumors with coagulative tumor cell necrosis alone were clinically LMS. In those cases in which the type of necrosis is uncertain (coagulative tumor cell vs. hyalinized), the addition of p16 may aid in discerning a subset of STUMP that should be classified as LMS.

Expression of the urothelial differentiation markers GATA3 and placental S100 (S100P) in female genital tract transitional cell proliferations.

The degree of urothelial differentiation in putative transitional (urothelial) proliferations in the female genital tract is still controversial. To further investigate the similarities (or dissimilarities) between female genital tract transitional proliferations and bladder urothelium, we evaluated the expression of S100P and GATA3, 2 proteins that we previously found to be strongly expressed in bladder urothelial tumors, in 25 benign ovarian Brenner tumors, 19 Walthard cell nests (17 tubal and 2 ovarian hilus), 1 mature teratoma with a benign urothelial proliferation, 2 proliferating (borderline) ovarian Brenner tumors, 1 malignant Brenner tumor, and 12 ovarian transitional cell carcinomas (TCC). Each lesion was also evaluated for p63 expression by immunohistochemistry. Immunostaining was performed on formalin-fixed, paraffin-embedded tissue sections using the avidin–biotin-peroxidase complex method. Eighty-eight percent of Brenner tumors were positive for S100P, whereas 96% and 100% were positive for GATA3 and p63, respectively. One of 2 proliferating Brenner tumors was positive for S100P, whereas both cases were positive for GATA3 and p63; the malignant Brenner tumor was positive for S100P and p63, but negative for GATA3. Only 17% of TCC were positive for S100p, whereas 33% and 50% of TCC were positive for GATA3 and p63, respectively. Tubal Walthard cell nests were either completely negative or showed only scattered positive staining for S100P; in contrast, 89.5% and 100% of Walthard nests, including the 2 ovarian cases were positive for GATA3 and p63. The teratoma-associated benign urothelial proliferation was also negative for S100P, but positive for GATA3 and p63. Although proliferating and malignant Brenner tumors may exhibit a more intermediate immunoprofile, expression of S100P, GATA3, and p63 by a majority of ovarian Brenner tumors underscores the similarity between these neoplasms and urothelial proliferations of bladder origin. The indeterminate phenotype seen in Walthard nests and ovarian TCC suggests that these proliferations may represent an incomplete or alternate form of differentiation.

The diagnosis of endometrial carcinomas with clear cells by gynecologic pathologists: An assessment of interobserver variability and associated morphologic features

The purposes of this study are to assess the level of interobserver variability in the diagnosis of endometrial carcinomas with clear cells by gynecologic pathologists based purely on their morphologic features and to comparatively describe the cases of putative clear cell carcinoma (CCC) with and without significant interobserver variability. A total of 35 endometrial carcinomas (1 slide per case) were reviewed by 11 gynecologic pathologists (median experience: 10 y) from 11 North American institutions. The cases were selected from the files of 3 institutions on the basis of the presence of at least focal clear cells and had previously been classified as a variety of histotypes at these institutions. Diagnoses were rendered in a blinded manner and without predetermined diagnostic criteria or categories. The &kgr; values between any pair of observers ranged from 0.18 to 0.69 (combined 0.46), which was indicative of a “moderate” level of interobserver agreement for the group. Subgroups of “confirmed CCC” [cases diagnosed as such by at least 8 (73%) of the 11 observers, n=14] and “possible CCC” (cases diagnosed as CCC by ≥1 but <8 observers, n=13) were compared with regard to a variety of semiquantified morphologic features. By combining selected morphologic features that displayed statistically significant differences between the 2 groups on univariate analyses, the following approximate morphologic profile emerged for the confirmed CCC group: papillae with hyalinized cores in ≥33% of the lesion, clear cells in ≥33% of the lesion, hyperchromasia in ≥33% of the lesion, the absence of nuclear pseudostratification in >3 cells on the papillae, the absence of nuclear pseudostratification in glands in ≥33% of the lesion, the absence of diffuse grade 3 nuclei, the absence of long and slender papillae in ≥33% of the lesion, and glands and papillae lined by cuboidal to flat, noncolumnar cells. In a backward stepwise logistic regression analysis, features from the profile that predicted the confirmed CCC group included: (1) absence or minimality of diffuse sheets of grade 3 nuclei [P=0.025; 95% confidence interval (CI), 0.0266-0.363]; (2) absence or minimality of nuclear stratification in glands and papillae (P=0.040; 95% CI, −0.228 to −0.0054); and (3) glands and papillae lined by cuboidal to flat, noncolumnar cells (P=0.008; 95% CI, 0.0911-0.566). The 2 groups displayed significant overlap regarding a wide variety of features, and no single case displayed a full complement of potentially diagnostic features. Morphologic patterns associated with cases with very high levels of interobserver variability (defined as cases with ≥4 different diagnoses rendered for them, n=9) included the near-exclusive or exclusively solid pattern of clear cells (3/9) and glandular/papillary proliferations whose only CCC-like feature was the presence of clear cells (2/9). In conclusion, the diagnosis of endometrial carcinomas with clear cells by gynecologic pathologists is associated with a moderate level of interobserver variability. However, there is a morphologic profile that characterizes cases that gynecologic pathologists more uniformly classify as CCC, and the presence of these features is supportive of a CCC diagnosis in an endometrial carcinoma with clear cells. Cases that display broad and significant qualitative deviations from the aforementioned profile should prompt the consideration of a diagnosis other than CCC.

A time- and matrix-dependent TGFBR3–JUND–KRT5 regulatory circuit in single breast epithelial cells and basal-like premalignancies

Basal-like breast carcinoma is characterized by poor prognosis and high intratumour heterogeneity. In an immortalized basal-like breast epithelial cell line, we identified two anticorrelated gene-expression programs that arise among single extracellular matrix (ECM)-attached cells during organotypic three-dimensional culture. The first contains multiple TGF-β-related genes including TGFBR3, whereas the second contains JUND and the basal-like marker KRT5. TGFBR3 and JUND interconnect through four negative-feedback loops to form a circuit that exhibits spontaneous damped oscillations in three-dimensional culture. The TGFBR3–JUND circuit is conserved in some premalignant lesions that heterogeneously express KRT5. The circuit depends on ECM engagement, as detachment causes a rewiring that is triggered by RPS6 dephosphorylation and maintained by juxtacrine tenascin C, which is critical for intraductal colonization of basal-like breast cancer cells in vivo. Intratumour heterogeneity need not stem from partial differentiation and could instead reflect dynamic toggling of cells between expression states that are not cell autonomous.

The effect of intraoperative specimen inking on lumpectomy re-excision rates

BackgroundLumpectomy re-excision to obtain negative margins is common. We compare the effect of two specimen orientation approaches on lumpectomy re-excision rates.MethodsAll women undergoing lumpectomy for breast cancer by a single surgeon between 03/2007 - 02/2009 were included. Lumpectomies underwent standard inking (SI) after surgery by a pathologist from 03/2007-02/2008 while intraoperative inking (II) with direct surgeon input was done from 03/2008-02/2009. Rates of margin positivity and re-excision were compared between these methods.Results65 patients were evaluated, reflecting SI in 39 and II in 26 cases. Margin positivity rates of 46% [SI] vs. 23% [II] (p = 0.06) and re-excision rates of 38% [SI] vs. 19% [II] were observed. Residual disease at re-excision was found in 27% [SI] vs. 67% [II] of cases.ConclusionsIntraoperative inking in this practice offered a simple way to reduce re-excision rates after lumpectomy and affect an improvement in quality of patient care.

PD-L1 Expression and Intratumoral Heterogeneity Across Breast Cancer Subtypes and Stages: An Assessment of 245 Primary and 40 Metastatic Tumors.

Tumor expression of programmed cell death ligand 1 (PD-L1) is associated with immune evasion in a variety of malignancies, including a subset of triple-negative breast carcinomas, and may mark cancers as susceptible to PD-1/PD-L1 inhibitor therapies. We herein characterize PD-L1 expression in breast cancers across the full range of histomorphologies and investigate its intratumoral heterogeneity and fidelity across primaries and metastases. A total of 245 primary and 40 metastatic (20 nodal, 20 distant) breast carcinomas were evaluated with PD-L1 immunohistochemistry on tissue microarray. Tumor PD-L1 staining was seen in 12% of all primaries including 32% of triple-negative cancers. Staining was common in ductal cancers with medullary (54%), apocrine (27%), and metaplastic features (40%). However, diffuse (>50%) staining was rare (2% of all cancers and 5% of triple negatives). Immune staining was seen in 29% of all primaries and 61% of triple negatives. Tumor expression of PD-L1 was conserved in 94% of matched primary/metastasis pairs, while immune staining showed fidelity in 71%; the remaining cases acquired PD-L1 immune cell expression in the metastasis. Only half of cases with positive tumor staining showed concordance across all analyzed cores. These data demonstrate that PD-L1 expression is prevalent among high-grade, hormone receptor–negative breast cancers with a range of histomorphologies and shows fidelity between primary and metastatic sites in treatment-naive cancers, although acquisition of immune PD-L1 staining in metastases is not uncommon. There is considerable intratumoral heterogeneity in PD-L1 expression, undermining the suitability of core biopsy in the determination of PD-L1 status. Clinical trials are needed to determine PD-L1 staining thresholds required for therapeutic response, as diffuse staining is rare.

Podoplanin expression in basal and myoepithelial cells: utility and potential pitfalls.

Podoplanin, D2-40, is often used for highlighting lymphatics. However, it has been described in a variety of normal and neoplastic tissues. We evaluated the expression of D2-40 in breast, salivary gland, skin, and mucosa, all organs rich in myoepithelial cells and basal cells. This study assessed the utility of using D2-40 to highlight basal/myoepithelial cells and to identify potential pitfalls in misinterpretation of lymphatic invasion. Our results showed that myoepithelial cells in breast and salivary gland and basal cells in prostate consistently demonstrate D2-40 immunoreactivity, but typically less intensely than lymphatics. Cutaneous and mucosal-based basal cells also have D2-40 expression, but often in a patchy, focal manner. In addition, many salivary gland tumors and squamous cell carcinomas had strong D2-40 expression, sometimes making distinction of lymphatics versus tumor edge staining difficult. D2-40 is excellent for assessing lymphatic invasion in breast, prostate, and cervix as long as the pathologist is aware of the expression in myoepithelial cells/basal cells to avoid misinterpretation of ductal carcinoma in situ or normal prostate glands or tumor stroma retraction as tumor lymphatic invasion. Given the patchy positivity in basal cells of skin and mucosa and the reactivity in squamous cell carcinoma, D2-40 was not helpful in assessing for microinvasion of squamous cell carcinoma.

Clinicopathologic Comparison of Lynch Syndrome-associated and "Lynch-like" Endometrial Carcinomas Identified on Universal Screening Using Mismatch Repair Protein Immunohistochemistry.

Expanded testing for Lynch syndrome (LS) is increasingly recommended for patients with endometrial carcinomas, and immunohistochemistry (IHC) for tumor loss of mismatch-repair (MMR) protein expression is the most common primary screen. This has led to the recognition of MMR-IHC–deficient cases without identifiable mutations on directed germline sequencing. The clinical implications of such “Lynch-like” (LL) cancers are unclear. We here report the clinicopathologic features of putative familial endometrial carcinoma identified on universal MMR-IHC screening with attention to cases with discordant IHC and germline results. The files of the University of Virginia Pathology Department were retrospectively searched for all MMR-deficient endometrial carcinomas identified on screening. Cases were categorized as likely sporadic (MLH1/PMS2 loss, evidence of MLH1 promoter hypermethylation) or putative LS (PLS) (loss of MSH2/MSH6, MSH6, or PMS2). PLS cases were further subdivided into LS and LL groups on the basis of the presence or absence of a confirmatory mutation by germline testing, and the clinicopathologic features of these cases were compared. A deficiency of ≥1 MMR protein was observed in 31.4% (66/210) of endometrial carcinomas, including 26 PLS cases, 15 of which had germline testing. Directed germline sequencing confirmed LS in 46.7% (7/15); the remaining cases were classified as LL. High-grade and/or biphasic morphology was seen in 42.9% (3/7) of LS and 62.5% (5/8) of LL cases; the remaining cases showed low-grade, conventional endometrioid morphology. High level microsatellite instability was observed in 71.4% (5/7) of LL cases. The majority of cases from both groups (LS: 85.7% [6/7]; LL: 87.5% [7/8]) were low-stage (T1a/T1b). Endometrial carcinoma was the presenting malignancy in 85.7% (6/7) of LS patients and 87.5% (7/8) of LL patients. Family history was suggestive of LS in 28.5% (2/7) of LS patients and 12.5% (1/8) of LL patients. Screening algorithms based on age and cancer history would have failed to identify LS patients in 57.1% (4/7) of cases. Although universal MMR-IHC identifies endometrial carcinoma patients with LS who would have been missed using targeted screening algorithms, it also identifies cancers with discordant IHC and germline results for which the somatic versus germline origin of the MMR defect is unclear. Further study of this LL group is required before drawing definitive conclusions about their familial cancer risk.