Re-evaluation of the methodology for estimating the US specialty physician workforce.

Increasing pursuit of subspecialized training has quietly revolutionized physician training, but the potential impact on physician workforce estimates has not previously been recognized. The Physicians Specialty Data Reports of the Association of American Medical Colleges, derived from specialty designations in the American Medical Association (AMA) Physician Professional Data (PPD), are the reference source for US physician workforce estimates; by 2020, the report for pathologists was an undercount of 39% when compared with the PPD. Most of the difference was due to the omission of pathology subspecialty designations. The rest resulted from reliance on only the first of the AMA PPD's 2 specialty data fields. Placement of specialty designation in these 2 fields is sensitive to sequence of training and is thus affected by multiple or intercalated (between years of residency training) fellowships. Both these phenomena have become progressively more common and are not unique to pathology. Our findings demonstrate the need to update definitions and methodology underlying estimates of the US physician workforce for pathology and suggest a like need in other specialties affected by similar trends.

An Update on Prenatal Diethylstilbestrol Exposure and High-Grade Squamous Intraepithelial Lesions of the Lower Genital Tract.

Women with prenatal diethylstilbestrol exposure are excluded from less frequent cervical cancer screening because of their increased neoplasia risk. We report the results of a prospective follow-up study of prenatal diethylstilbestrol exposure and lower genital tract high-grade (grade 2 or higher) squamous intraepithelial lesions (HSIL). The age-adjusted risk of HSIL among diethylstilbestrol-exposed women (n=4,062) was higher than among the diethylstilbestrol unexposed (n=1,837) through age 44 years (hazard ratio 2.03, 95% CI, 1.31-3.14) but not age 45 years or older. Elevated HSIL risk remained higher in diethylstilbestrol-exposed women, after accounting for frequency of cervical cancer screening. Compared with unexposed women, HSIL risk was higher among women with earlier gestational and high-dose diethylstilbestrol exposure. These data confirm the appropriateness of more frequent screening among diethylstilbestrol-exposed women through age 44 years. Whether those aged 45 years or older should continue to have increased screening will require careful weighing of possible risks and benefits.

Strong Job Market for Pathologists: Results From the 2021 College of American Pathologists Practice Leader Survey.

CONTEXT.­: There has long been debate about whether and when there may be a shortage of pathologists in the United States. One way to assess this is to survey the hiring experiences of pathology practices. A 2018 survey revealed a strong demand for pathologists, with expectations of continued strength. This study updates that prior analysis using data from a 2021 survey of pathology practice leaders. OBJECTIVE.­: To assess the US pathologist job market and examine implications. DESIGN.­: We analyzed data from the 2021 College of American Pathologists Practice Leader Survey. This survey queried practice leaders, including regarding the hiring of pathologists, the level of experience being sought, success in filling positions, and expectations for hiring in the next 3 years. RESULTS.­: Among the 375 surveyed practice leaders (about one-third of all US pathology practices), 282 provided information about pathologist hiring in 2021. A total of 157 of these 282 practices (55.7%) sought to hire at least 1 pathologist in 2021, up from 116 of 256 practices (45.3%) in 2017; the mean number of pathologists hired per practice also increased. In 2021, a total of 175 of 385 positions (45.5%) were to fill new positions, compared with 95 of 249 positions (38.2%) in 2017. Most practice leaders were comfortable hiring pathologists with less than 2 years of posttraining experience. Practice leaders anticipated continued strong demand for hiring pathologists during the next 3 years. CONCLUSIONS.­: Our analysis confirms that the demand in pathologist hiring is strong and much increased from 2017. We believe, in combination with other job market indicators, that demand may outstrip the supply of pathologists, which is limited by the number of trainees and has remained constant during the past 20 years.

Features of burnout amongst pathologists: A reassessment.

There has been little rigorous assessment of burnout among pathologists and pathology trainees. Given this relative dearth of relevant literature on pathologist burnout, this report aims to raise awareness of the issue among those working in and around this specialty. Our results are based on a survey given in conjunction with the American Board of Pathology's (ABPath) biennial Continuing Certification (CC) reporting of activities required of diplomates to maintain certification. The survey was voluntary, open to all diplomates participating in CC, and conducted over two consecutive years (2019 and 2020), with alternate years comprising different sets of diplomates. The data are based on 1256 respondents (820 from 2019 to 436 from 2020). The three highest aggregate reported rates of burnout (reported as experienced nearly all of the time, most of the time, or part of the time) occurred when respondents were in their first year of residency training (41.1%) and when they were in (47.6%) and beyond (46.6%) their first three years of practice. We considered this high-low-high, or U-shaped distribution in recollected burnout over time among pathologists a notable finding and investigated its distribution among respondents. Conversely at every point in their training and practice, from half to three-quarters of respondents reported never or infrequently experiencing burnout. This study represents the largest pathologist cohort survey to date about pathologists' burnout. Importantly, especially for those considering pathology as a career, these data are on the low end of the distribution of burnout among specialties for those in practice.

Evidence-Based Alignment of Pathology Residency With Practice II: Findings and Implications.

This article presents findings from a 4-year series of surveys of new-in-practice pathologists, and a survey of physician employers of new pathologists, assessing how pathology graduate medical education prepares its graduates for practice. Using the methodology described in our previous study, we develop evidence for the importance of residency training for various practice areas, comparing findings over different practice settings, sizes, and lengths of time in practice. The principal findings are (1) while new-in-practice pathologists and their employers report residency generally prepared them well for practice, some areas-billing and coding, laboratory management, molecular pathology, and pathology informatics-consistently were identified as being important in practice but inadequately prepared for in residency; (2) other areas-autopsy pathology, and subspecialized apheresis and blood donor center blood banking services-consistently were identified as relatively unimportant in practice and excessively prepared for in residency; (3) the notion of a single comprehensive model for categorical training in residency is challenged by the disparity between broad general practice in some settings and narrower subspecialty practice in others; and (4) the need for preparation in some areas evolves during practice, raising questions about the appropriate mode and circumstance for training in these areas. The implications of these findings range from rebalancing the emphasis among practice areas in residency, to reconsidering the structure of graduate medical education in pathology to meet present and evolving future practice needs.

Evaluation of Host Immune Cellular and Extracellular Matrix Responses to Prolapse Mesh With and Without Tension in a Rat Model.

OBJECTIVES: We sought to determine whether vaginal host immune cellular and extracellular matrix responses are altered in a rat sacrocolpopexy model when lightweight polypropylene mesh is attached on tension versus without tension. METHODS: We performed hysterectomy and ovariectomy in 32 Sprague-Dawley rats. Animals were assigned to 4 groups (n = 8/group): (1) controls with sham operation only (control), (2) mesh sutured only on the vagina (vaginal mesh), (3) sacrocolpopexy without tension, and (4) sacrocolpopexy with tension. Ninety days later, we excised vagina-mesh complexes. A histomorphologic scoring system of hematoxylin/eosin and Masson trichrome stained slides was used to assess host inflammatory responses. The cellular inflammatory response was further quantified using (1) identification of M1 and M2 macrophage subsets and (2) quantification of proinflammatory and anti-inflammatory cytokines. The extracellular matrix response was evaluated by measuring (1) matrix metalloproteinase-2 and matrix metalloproteinase-9 levels and (2) type I/III collagen. RESULTS: Histomorphological tissue responses were greater in all groups with mesh compared with sham controls. Both sacrocolpopexy groups had similar scores, but each group scored significantly higher than the vaginal mesh group. Among the 4 groups, there were no statistically significant differences in M1 or M2 macrophage subsets, proinflammatory or anti-inflammatory cytokines, or extracellular matrix remodeling responses. CONCLUSIONS: Attachment of prolapse mesh resulted in an increased histologic inflammatory response independent of tension. Other markers of cellular inflammation and extracellular matrix remodeling showed no differences among experimental groups. Tension on lightweight polypropylene mesh did not significantly alter the host response in this rat sacrocolpopexy model.

Polycarbonate Urethane Mesh: A New Material for Pelvic Reconstruction.

OBJECTIVE: Polycarbonate urethane (PCU) is a new biomaterial, and its mechanical properties can be tailored to match that of vaginal tissue. We aimed to determine whether vaginal host immune and extracellular matrix responses differ after PCU versus lightweight polypropylene (PP) mesh implantation. METHODS: Hysterectomy and ovariectomy were performed on 24 Sprague-Dawley rats. Animals were divided into 3 groups: (1) PCU vaginal mesh, (2) PP vaginal mesh, and (3) sham controls. Vagina-mesh complexes or vaginas (controls) were excised 90 days after surgery. We quantified responses by comparing: (1) histomorphologic scoring of hematoxylin and eosin- and Masson trichrome-stained slides, (2) macrophage subsets (immunolabeling), (3) pro-inflammatory and anti-inflammatory cytokines (Luminex panel), (4) matrix metalloproteinase (MMP)-2 and -9 using an enzyme-linked immunosorbent assay, and (5) type I/III collagen using picrosirius red staining. RESULTS: There was no difference in histomorphologic score between PCU and PP (P = 0.211). Although the histomorphologic response was low surrounding all mesh fibers, groups with PCU and PP mesh had a higher histomorphologic score than the control group (P < 0.005 and P < 0.002, respectively). There were no differences between groups in terms of macrophage subsets, pro-inflammatory cytokines, anti-inflammatory cytokines, MMP-2 and MMP-9, or collagen ratio. CONCLUSIONS: Polycarbonate urethane, an elastomer with material properties similar to those of vaginal tissue, elicits minimal host inflammatory responses in a rat model. Because its implantation does not elicit more inflammation than currently used lightweight PP, using PCU for prolapse mesh warrants further investigation with larger animal models.

Social Media Engagement at Academic Conferences: Report of the Association of Pathology Chairs 2018 and 2019 Annual Meeting Social Media Committee.

The use of social media at academic conferences is expanding, and platforms such as Twitter are used to share meeting content with the world. Pathology conferences are no exception, and recently, pathology organizations have promoted social media as a way to enhance meeting exposure. A social media committee was formed ad hoc to implement strategies to enhance social media involvement and coverage at the 2018 and 2019 annual meetings of the Association of Pathology Chairs. This organized approach resulted in an 11-fold increase in social media engagement compared to the year prior to committee formation (2017). In this article, the social media committee reviews the strategies that were employed and the resultant outcome data. In addition, we categorize tweets by topic to identify the topics of greatest interest to meeting participants, and we discuss the differences between Twitter and other social media platforms. Lastly, we review the existing literature on this topic from 23 medical specialties and health care fields.

Reevaluation of the US Pathologist Workforce Size.

Importance: There is currently no national organization that publishes its data that serves as the authoritative source of the pathologist workforce in the US. Accurate physician numbers are needed to plan for future health care service requirements. Objective: To assess the accuracy of current pathologist workforce estimates in the US by examining why divergency appears in different published resources. Design, Setting, and Participants: This study examined the American Board of Pathology classification for pathologist primary specialty and subspecialties and analyzed previously published reports from the following data sources: the Association of American Medical Colleges (AAMC), the Accreditation Council for Graduate Medical Education (ACGME), a 2013 College of American Pathologists (CAP) report, a commercially available version of the American Medical Assoication (AMA) Physician Masterfile, and an unpublished data summary from June 10, 2019. Main Outcomes and Measures: Number of physicians classified as pathologists. Results: The most recent AAMC data from 2017 (published in 2018) reported 12 839 physicians practicing "anatomic/clinical pathology," which is a subset of the whole. In comparison, the current AMA Physician Masterfile, which is not available publicly, listed 21 292 active pathologists in June 2019. The AMA Physician Masterfile includes all pathologists in 15 subspecialized training areas as identified by the ACGME. By contrast, AAMC's data, which derive from the AMA Physician Masterfile data, only count physicians primarily associated with 3 general categories of pathologists and 1 subspecialty category (ie, chemical pathology). Thus, the AAMC pathology workforce estimate does not include those whose principal work is in 11 subspecialty areas, such as blood banking or transfusion medicine, cytopathology, hematopathology, or microbiology. An additional discrepancy relates to the ACGME residency (specialties) and fellowship (subspecialties) training programs in which pathologists with training in dermatopathology appear as dermatologists and pathologists with training in molecular genetic pathology appear as medical geneticists. Conclusions and Relevance: This analysis found that most sources reported only select categories of the pathologist workforce rather than the complete workforce. The discordant nature of reporting may pertain to other medical specialties that have undergone increased subspecialization during the past 2 decades (eg, surgery and medicine). Reconsideration of the methods for determining the pathologist workforce and for all workforces in medicine appears to be needed.

The State of the Job Market for Pathologists: Evidence From the College of American Pathologists Practice Leader Survey.

CONTEXT.­: Disagreement exists within the pathology community about the status of the job market for pathologists. Although many agree that jobs in pathology were harder to come by earlier this decade, recent evidence suggests improvement is occurring. OBJECTIVE.­: To assess the state of the job market for pathologists. DESIGN.­: We analyzed data from the 2018 College of American Pathologists Practice Leader Survey. This survey contains data from 253 practice leaders on practices' hiring (and retrenchments) in 2017, the skills and level of experience being sought, success in filling those positions, and expectations for hiring in the next 3 years. RESULTS.­: Among the surveyed practice leaders, 115 (45.5%) sought to hire at least 1 pathologist in 2017, and together tried to fill 246 full-time equivalent positions that year, of which 93.5 full-time equivalents (38%) were newly created. This hiring was not limited to larger, academic-based practices, but also occurred among smaller practices and practices based in nonacademic hospitals, independent laboratories, and other settings. Although some practices retrenched (60 full-time equivalents in 2017), the net increase was a healthy 187 full-time equivalents. Practices most frequently sought pathologists who had at least 2 years of experience, but the level of experience identified with the "optimal" candidate varied by desired areas of subspecialty expertise. Practice leaders also reported expected growth in hiring, with the number of positions they hope to fill in the next 3 years exceeding those vacated by retirement. CONCLUSIONS.­: Our findings support the proposition that the demand for pathologists is strong, at least at the current time.

Whole-Genome and Segmental Homozygosity Confirm Errors in Meiosis as Etiology of Struma Ovarii.

Strumae ovarii are neoplasms composed of normal-appearing thyroid tissue that occur within the ovary and rarely spread to extraovarian sites. A unique case of struma ovarii with widespread dissemination detected 48 years after removal of a pelvic dermoid provided the opportunity to reexamine the molecular nature of this form of neoplasm. One tumor, from the heart, consisting of benign thyroid tissue was found to have whole-genome homozygosity. Another tumor from the right mandible composed of malignant-appearing thyroid tissue showed whole-genome homozygosity and a deletion of 7p, presumably the second hit that transformed it into a cancerous tumor. Specimens from 2 other cases of extraovarian struma confined to the abdomen and 8 of 9 cases of intraovarian struma showed genome-wide segmental homozygosity. These findings confirm errors in meiosis as the origin of struma ovarii. The histological and molecular findings further demonstrate that even when outside the ovary, strumae ovarii can behave nonaggressively until they receive a second hit, thereafter behaving like cancer.

Reproductive tract biology: Of mice and men.

The study of male and female reproductive tract development requires expertise in two separate disciplines, developmental biology and endocrinology. For ease of experimentation and economy, the mouse has been used extensively as a model for human development and pathogenesis, and for the most part similarities in developmental processes and hormone action provide ample justification for the relevance of mouse models for human reproductive tract development. Indeed, there are many examples describing the phenotype of human genetic disorders that have a reasonably comparable phenotype in mice, attesting to the congruence between mouse and human development. However, anatomic, developmental and endocrinologic differences exist between mice and humans that (1) must be appreciated and (2) considered with caution when extrapolating information between all animal models and humans. It is critical that the investigator be aware of both the similarities and differences in organogenesis and hormone action within male and female reproductive tracts so as to focus on those features of mouse models with clear relevance to human development/pathology. This review, written by a team with extensive expertise in the anatomy, developmental biology and endocrinology of both mouse and human urogenital tracts, focusses upon the significant human/mouse differences, and when appropriate voices a cautionary note regarding extrapolation of mouse models for understanding development of human male and female reproductive tracts.

Prenatal diethylstilbestrol exposure and cancer risk in women.

In the Diethylstilbestrol [DES] Combined Cohort Follow-up, the age- and calendar-year specific standardized incidence ratio [SIR] for clear cell adenocarcinoma [CCA] was 27.6 (95% confidence interval [CI] 7.51-70.6) for the exposed women. The SIR for breast cancer was 1.17 (95% CI 1.01-1.36) and the hazard ratio [HR] adjusted for birth year and cohort for comparison with the unexposed was 1.05 (95% CI 0.79-1.41). The SIR for pancreatic cancer was 2.43 (95% CI 1.21-4.34) and the adjusted HR for comparison with unexposed women was 7.16 (95% CI 0.84-61.5). There was little evidence of excess risk for other sites. There appeared to be a deficit in risk for endometrial cancer among the exposed (SIR 0.61; 95% CI 0.35-0.98), and an excess in the unexposed (SIR 1.55; 95% CI 0.95-2.40); the adjusted HR was 0.45 (95% CI 0.22-0.93) for the internal comparison. There was no overall excess cancer risk in exposed women compared with general population rates (1.06; 95% CI 0.95-1.17) or with unexposed participants (adjusted HR 1.03; 95% CI 0.84-1.25). These data do not support the suggestion that there is a diathesis of cancers in DES exposed female offspring The excess risk of breast and pancreatic cancers that we observed is concerning and warrants continued follow-up and mechanistic investigation. Environ. Mol. Mutagen. 60:395-403, 2019. Published 2017. This article is a US Government work and is in the public domain in the USA.

The Life Cycle of the Uterine Fibroid Myocyte.

PURPOSE OF REVIEW: Uterine fibroids are common benign tumors of women in the USA and worldwide, yet the biological nature and pathogenesis of these tumors remain largely unknown. This review presents our view of the stages in the life cycle of a subset of uterine fibroid myocytes, introduces hypothetical concepts and morphological data to explain these changes, and relates these changes in individual myocytes to the phases of fibroid tumor development. RECENT FINDINGS: The observations gained from light and electron microscopic, immunohistochemical, and morphometric studies in our laboratory have led to the hypothesis that fibroid changes over time may relate to the excessive production of collagen by phenotypically transformed myocytes. This accumulation of collagen results in decreased microvessel density, followed by myocyte injury and atrophy, with eventual senescence and involution through ischemic cellular degeneration and inanition. SUMMARY: Uterine leiomyomas, or fibroids, are characterized by two histologic features-proliferation of myocytes and production of an extracellular collagenous matrix. In the larger tumors, the collagenous matrix is often abundant. Within those regions in which the accumulating collagen is excessive, the myocytes are progressively separated from their blood supply, resulting in myocyte atrophy and eventually cell death. It is within these hypocellular, hyalinized areas that the complete lifecycle of the fibroid myocyte is realized. It begins with the phenotypic transformation of a contractile cell to one characterized by proliferation and collagen synthesis, progresses through an intermediate stage of atrophy related to interstitial ischemia, and eventuates in cell death due to inanition. Lastly, resorption of inanotic cells appears to occur by a non-phagocytic, presumably enzymatic process of degradation and recycling that we refer to as reclamation.

Development of the human female reproductive tract.

Development of the human female reproductive tract is reviewed from the ambisexual stage to advanced development of the uterine tube, uterine corpus, uterine cervix and vagina at 22 weeks. Historically this topic has been under-represented in the literature, and for the most part is based upon hematoxylin and eosin stained sections. Recent immunohistochemical studies for PAX2 (reactive with Müllerian epithelium) and FOXA1 (reactive with urogenital sinus epithelium and its known pelvic derivatives) shed light on an age-old debate on the derivation of vaginal epithelium supporting the idea that human vaginal epithelium derives solely from urogenital sinus epithelium. Aside for the vagina, most of the female reproductive tract is derived from the Müllerian ducts, which fuse in the midline to form the uterovaginal canal, the precursor of uterine corpus and uterine cervix an important player in vaginal development as well. Epithelial and mesenchymal differentiation markers are described during human female reproductive tract development (keratins, homeobox proteins (HOXA11 and ISL1), steroid receptors (estrogen receptor alpha and progesterone receptor), transcription factors and signaling molecules (TP63 and RUNX1), which are expressed in a temporally and spatially dynamic fashion. The utility of xenografts and epithelial-mesenchymal tissue recombination studies are reviewed.

Evidence-Based Alignment of Pathology Residency With Practice: Methodology and General Consideration of Results.

Few medical specialties engage in ongoing, organized data collection to assess how graduate medical education in their disciplines align with practice. Pathology educators, the American Board of Pathology, and major pathology organizations undertook an evidence-based, empirical assessment of what all pathologists need to learn in categorical residency. Two challenges were known when we commenced and we encountered 2 others during the project; all were ultimately satisfactorily addressed. Initial challenges were (1) ensuring broad representation of the new-in-practice pathologist experience and (2) adjusting for the effect on this experience of subspecialty fellowship(s) occurring between residency and practice. Additional challenges were (3) needing to assess and quantify degree and extent of subspecialization in different practice settings and (4) measuring changing practice responsibilities with increasing time in practice. We instituted annual surveys of pathologists who are relatively new (<10 years) in practice and a survey of physician employers of new pathologists. The purpose of these surveys was to inform (1) the American Board of Pathology certification process, which needs to assess the most critical knowledge, judgment, and skills required by newly practicing pathologists, and (2) pathology graduate medical education training requirements, which need to be both efficient and effective in graduating competent practitioners. This article presents a survey methodology to evaluate alignment of graduate medical education training with the skills needed for new-in-practice physicians, illustrates an easily interpreted graphical format for assessing survey data, and provides high-level results showing consistency of findings between similar populations of respondents, and between new-in-practice physicians and physician-employers.

Tissue interactions and estrogenic response during human female fetal reproductive tract development.

The role of tissue interactions was explored to determine whether epithelial differentiation within the developing human reproductive tract is induced and specified by mesenchyme in tissue recombinants composed of mouse vaginal mesenchyme + human uterine tubal epithelium (mVgM+hTubE). The tissue recombinants were grown in DES-treated ovariectomized athymic mice. After 2-4 weeks of in vivo growth, several vaginal specific features were expressed in the human tubal epithelium. The mesenchyme-induced effects included morphological change as well as expression of several immunohistochemical markers. Although the mesenchyme-induced shift in vaginal differentiation in the human tubal epithelium was not complete, the partial induction of vaginal markers in human tubal epithelium verifies the importance of mesenchymal-epithelial interactions in development of the human female reproductive tract. In a separate experiment, DES-induction of uterine epithelial progesterone receptor (PGR) and estrogen receptor 1 (ESR1) was explored in tissue recombinants composed of wild-type or Esr1KO mouse uterine mesenchyme + human fetal uterine epithelium (wt UtM+hUtE and Esr1KO UtM+hUtE). The rationale of this experiment was to determine whether DES-induction of PGR and ESR1 is mediated directly via epithelial ESR1 or indirectly (paracrine mechanism) via mesenchymal ESR1. DES-induction of uterine epithelial ESR1 and PGR in Esr1KO UtM+hUtE tissue recombinants (devoid of mesenchymal ESR1) formally eliminates the paracrine mechanism and demonstrates that DES induction of human uterine epithelial ESR1 and PGR is directly mediated via epithelial ESR1.

A Review and Update on Papillary Immature Metaplasia of the Uterine Cervix: A Distinct Subset of Low-Grade Squamous Intraepithelial Lesion, Proposing a Possible Cell of Origin.

CONTEXT: - Papillary immature metaplasia (PIM) is a known papillary cervical lesion associated with low-risk human papillomavirus (LR-HPV). OBJECTIVE: - To evaluate additional clinicopathologic features and the HPV genotypes of PIM and discuss the presumptive cell of origin. DESIGN: - A total of 26 PIM cases were evaluated by p16INK4a, cytokeratin (CK) 7, and CK17 immunohistochemical stainings. Human papillomavirus genotyping was performed, by using HPV DNA Chip, HPV polymerase chain reaction (PCR), and real-time PCR. RESULTS: - Histologically, PIM forms either a papillary mass (n = 21 of 26, 81%) or a slightly elevated/flat plaque (n = 5, 19%). All cases contain variable amounts of mucinous epithelia within the lesions. Koilocytosis was identified in 15 of the 26 cases (58%). Sixteen cases (61%) were associated with LR-HPV (types 6, 11, or 42), but 3 cases (12%) with high-risk (HR) HPV (16, 16/18, and 33), 2 cases (8%) with mixed LR- and HR-HPV (6/16 and 11/58), while 2 cases (8%) were negative, but p16INK4a immunostaining showed nonblock positivity in all cases. Eight (31%) had high-grade squamous intraepithelial lesion (HSIL) in the adjacent mucosa, 4 (50%) of which showed direct continuity. Identical HPV subtypes were confirmed in separately microdissected cases from PIM and adjacent HSIL. Most lesions (n = 24, 92%) expressed CK17 (reserve cell marker) in a bottom-heavy pattern and CK7 (squamocolumnar junction [SCJ] marker) in a top-heavy pattern, while most cases of low-grade squamous intraepithelial lesion (LSIL) were negative for both markers. CONCLUSIONS: - Our results suggest that PIM is a distinct subset of LSIL showing a productive HPV infection, but PIM involves the transformation zone and is proximal to SCJ, while LSIL is mostly from ectocervix or distal to the SCJ.

Response of xenografts of developing human female reproductive tracts to the synthetic estrogen, diethylstilbestrol.

Human female fetal reproductive tracts 9.5-22 weeks of gestation were grown for 1 month in ovariectomized athymic adult female mouse hosts that were either untreated or treated continuously with diethylstilbestrol (DES) via subcutaneous pellet. Normal morphogenesis and normal patterns of differentiation marker expression (KRT6, KRT7, KRT8, KRT10, KRT14, KRT19, ESR1, PGR, TP63, RUNX1, ISL1, HOXA11 and α-ACT2) were observed in xenografts grown in untreated hosts and mimicked observations of previously reported (Cunha et al., 2017) non-grafted specimens of comparable age. DES elicited several notable morphological affects: (a) induction of endometrial/cervical glands, (b) increased plication (folding) of tubal epithelium, (c) stratified squamous maturation of vaginal epithelium and (d) vaginal adenosis. DES also induced ESR1 in epithelia of the uterine corpus, cervix and globally induced PGR in most cells of the developing human female reproductive tract. Keratin expression (KRT6, KRT7, KRT8, KRT14 and KRT19) was minimally affected by DES. Simple columnar adenotic epithelium was devoid of TP63 and RUNX1, while DES-induced mature vaginal epithelium was positive for both transcription factors. Another striking effect of DES was observed in grafts of human uterine tube, in which DES perturbed smooth muscle patterning. These results define for the first time IHC protein markers of DES action on the developing human reproductive tract, which provide bio-endpoints of estrogen-induced teratogenesis in the developing human female reproductive tract for future testing of estrogenic endocrine disruptors.