Gender-Affirming Surgery and Cancer: Considerations for Radiation Oncologists for Pelvic Radiation in Transfeminine Patients.

Access to gender-affirming surgery is increasing for many transgender and nonbinary people in the United States, and radiation oncologists must be equipped to care for patients who have undergone such surgery in the region of their planned radiation treatment field. There are no guidelines for radiation treatment planning after gender-affirming surgery, and most oncologists do not receive training in the unique needs of transgender people with cancer. We review common gender-affirming genitopelvic surgeries for transfeminine people, including vaginoplasty, labiaplasty, and orchiectomy, and summarize the existing literature on the treatment of cancers of the neovagina, anus, rectum, prostate, and bladder in these patients. We also describe our systematic treatment approach and rationale for pelvic radiation treatment planning.

Survey of Clinical Providers and Allied Health Staff at a National Cancer Institute-Designated Comprehensive Cancer Center: Cultural Awareness in the Care of LGBTQ2S + Patients with Cancer.

To identify potential gaps in attitudes, knowledge, and practices towards LGBTQ2S + patients with a cancer diagnosis, a survey of clinical providers (CP) and allied health staff (AHS) was conducted to identify areas of improvement and guide development for future education and training. A previously published, validated survey was adapted at the direction of a LGBTQ2S + Patient and Family Advisory Council, and modified to include AHS. The survey was disseminated to all faculty and staff, and was adapted to the participants' self-identified level of patient interaction/care responsibilities. Subsections consisted of questions related to demographics, knowledge, attitudes, and practice behaviors towards participating in the care of LGBTQ2S + patients. Results were quantified using stratified analysis and an attitude summary measure. Of the 311 respondents, 179 self-identified as CPs and 132 as AHS. There was high agreement in comfort treating or assisting LGBTQ2S + patients by CP and AHS respondents, respectively. CPs possessed significantly higher knowledge regarding LGBTQ2S + health when compared to AHS; however, there remained high percentages of "neutral" and "do not know or prefer not to answer" responses regardless of clinical role. There was high agreement regarding the importance of knowing a patient's gender identity (GI) and pronouns (CP vs. AHS; 76.9% vs. 73.5% and 89.4% vs. 84.1%, respectively), whereas patient's sexual orientation and sex assigned at birth (CP vs. AHS; 51.1% vs. 53.5% and 58.6% vs. 62.9%, respectively) were viewed as less important. There was high interest in receiving education regarding the unique needs of LGBTQ2S + patients regardless of clinical role. Stratified analyses of CPs revealed early-career physicians (< 1-5 years from graduation) expressed higher interest in additional education and involvement with LGBTQ2S + -focused trainings when compared to mid- and late-career providers. This is the first study, to our knowledge, assessing the attitudes, knowledge, and practices of CPs and AHS regarding the care of LGBTQ2S + patients with cancer. Overall, there was high comfort treating/assisting LGBTQ2S + patients among CP and AHS respondents, respectively; yet, both groups possessed significant gaps in LGBTQ2S + -focused knowledge.

Disparities in cancer screenings for sexual and gender minorities.

Sexual and gender minorities (SGM) include persons identifying as lesbian, gay, bisexual, transgender/non-binary, and queer experience a greater cancer burden than their heterosexual or cisgender counterparts. Access to cancer care includes prevention and early detection, however despite known increased risk for various malignancies among SGM individuals, cancer screening rates remain low. This commentary outlines disparities in cancer screening for SGM individuals and provides the current evidence-based screening guidelines for these patients.

Acquired radioresistance in cancer associated fibroblasts is concomitant with enhanced antioxidant potential and DNA repair capacity.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are a major component of the cancer stroma, and their response to therapeutic treatments likely impacts the outcome. We tested the hypothesis that CAFs develop unique characteristics that enhance their resistance to ionizing radiation. METHODS: CAFs were generated through intimate coculture of normal human fibroblasts of skin or lung origin with various human cancer cell types using permeable microporous membrane inserts. Fibroblasts and cancer cells are grown intimately, yet separately, on either side of the insert's membrane for extended times to generate activated fibroblast populations highly enriched in CAFs. RESULTS: The generated CAFs exhibited a decrease in Caveolin-1 protein expression levels, a CAF biomarker, which was further enhanced when the coculture was maintained under in-vivo-like oxygen tension conditions. The level of p21Waf1 was also attenuated, a characteristic also associated with accelerated tumor growth. Furthermore, the generated CAFs experienced perturbations in their redox environment as demonstrated by increases in protein carbonylation, mitochondrial superoxide anion levels, and modulation of the activity of the antioxidants, manganese superoxide dismutase and catalase. Propagation of the isolated CAFs for 25 population doublings was associated with enhanced genomic instability and a decrease in expression of the senescence markers ß-galactosidase and p16INK4a. With relevance to radiotherapeutic treatments, CAFs in coculture with cancer cells of diverse origins (breast, brain, lung, and prostate) were resistant to the clastogenic effects of 137Cs γ rays compared to naïve fibroblasts. Addition of repair inhibitors of single- or double-stranded DNA breaks attenuated the resistance of CAFs to the clastogenic effects of γ rays, supporting a role for increased ability to repair DNA damage in CAF radioresistance. CONCLUSIONS: This study reveals that CAFs are radioresistant and experience significant changes in indices of oxidative metabolism. The CAFs that survive radiation treatment likely modulate the fate of the associated cancer cells. Identifying them together with their mode of communication with cancer cells, and eradicating them, particularly when they may exist at the margin of the radiotherapy planning target volume, may improve the efficacy of cancer treatments. Video Abstract.

Case-scenario exploration of cancer disparities experienced by gender minority persons.

Transgender, non-binary, and gender non-conforming people, also referred to as gender minorities, have unique cancer prevention, treatment, and care needs and experience cancer health disparities compared to the cisgender population. We present four composite cases of the cancer care challenges experienced by gender minorities.

The Case of Ty Jackson: An Interactive Module on LGBT Health Employing Introspective Techniques and Video-Based Case Discussion.

Introduction: The Institute of Medicine's 2011 report on lesbian, gay, bisexual, and transgender (LGBT) health and the legalization of same-sex marriage are just two of the numerous milestones that have hastened medical schools' efforts to prepare trainees to address the needs of LGBT community members. Early awareness of sexual diversity through self- and peer introspection and video-based education can help trainees build a foundation towards providing affirming care to LGBT patients. Methods: The Kern model was used to develop, implement, and evaluate an interactive multimodal workshop to provide first-year medical students with a formative introduction to LGBT health. Learning objectives focused on comprehending the spectrum of human sexuality, health issues for LGBT patients, and better practices for promoting affirming care. The module consisted of a PowerPoint presentation, sexuality survey, videos of provider-patient encounters, and community-based resources. Results: The workshop was implemented among 178 first-year medical students in September 2018, with 93% completing the pre-/postworkshop evaluations. Comparison of evaluations showed an increase in confidence in addressing each of the three learning objectives. Over 85% rated the PowerPoint and videos as very good or excellent. Discussion: This workshop was effective in helping first-year medical students appreciate the spectrum of sexual diversity, health issues facing LGBT individuals, and better practices to promote affirming care. The real-time sexuality survey helped trainees appreciate sexual diversity through self-reflection and near-peer sharing. The videos and accompanying discussion provided real-life encounters, along with common pitfalls in and pearls for communicating with LGBT patients.

Cellular Response to Exponentially Increasing and Decreasing Dose Rates: Implications for Treatment Planning in Targeted Radionuclide Therapy.

The treatment of cancer using targeted radionuclide therapy is of interest to nuclear medicine and radiation oncology because of its potential for killing tumor cells while minimizing dose-limiting toxicities to normal tissue. The ionizing radiations emitted by radiopharmaceuticals deliver radiation absorbed doses over protracted periods of time with continuously varying dose rates. As targeted radionuclide therapy becomes a more prominent part of cancer therapy, accurate models for estimating the biologically effective dose (BED) or equieffective dose (EQD2α/ß) will become essential for treatment planning. This study examines the radiobiological impact of the dose rate increase half-time during the uptake phase of the radiopharmaceutical. MDA-MB-231 human breast cancer cells and V79 Chinese hamster lung fibroblasts were irradiated chronically with 662 keV γ rays delivered with time-varying dose rates that are clinically relevant. The temporal dose-rate patterns were: 1. acute, 2. exponential decrease with a half-time of 64 h (Td = 64 h), 3. initial exponential increase to a maximum (half time Ti = 2, 8 or 24 h) followed by exponential decrease (Td = 64 h). Cell survival assays were conducted and surviving fractions were determined. There was a marked reduction in biological effect when Ti was increased. Cell survival data were tested against existing dose-response models to assess their capacity to predict response. Currently accepted models that are used in radiation oncology overestimated BED and EQD2α/ß at low-dose rates and underestimated them at high-dose rates. This appears to be caused by an adaptive response arising as a consequence of the initial low-dose-rate phase of exposure. An adaptive response function was derived that yields more accurate BED and EQD2α/ß values over the spectrum of dose rates and absorbed doses delivered. Our experimental data demonstrate a marked increase in cell survival when the dose-rate-increase half-time is increased, thereby suggesting an adaptive response arising as a consequence of this phase of exposure. We have modified conventional radiobiological models used in the clinic for brachytherapy and external beams of radiation to account for this phenomenon and facilitate their use for treatment planning in targeted radionuclide therapy.

A Mimic of the Tumor Microenvironment: A Simple Method for Generating Enriched Cell Populations and Investigating Intercellular Communication.

Understanding the early heterotypic interactions between cancer cells and the surrounding non-cancerous stroma is important in elucidating the events leading to stromal activation and establishment of the tumor microenvironment (TME). Several in vitro and in vivo models of the TME have been developed; however, in general these models do not readily permit isolation of individual cell populations, under non-perturbing conditions, for further study. To circumvent this difficulty, we have employed an in vitro TME model using a cell growth substrate consisting of a permeable microporous membrane insert that permits simple generation of highly enriched cell populations grown intimately, yet separately, on either side of the insert's membrane for extended co-culture times. Through use of this model, we are capable of generating greatly enriched cancer-associated fibroblast (CAF) populations from normal diploid human fibroblasts following co-culture (120 hr) with highly metastatic human breast carcinoma cells, without the use of fluorescent tagging and/or cell sorting. Additionally, by modulating the pore-size of the insert, we can control for the mode of intercellular communication (e.g., gap-junction communication, secreted factors) between the two heterotypic cell populations, which permits investigation of the mechanisms underlying the development of the TME, including the role of gap-junction permeability. This model serves as a valuable tool in enhancing our understanding of the initial events leading to cancer-stroma initiation, the early evolution of the TME, and the modulating effect of the stroma on the responses of cancer cells to therapeutic agents.

Is Ionizing Radiation Harmful at any Exposure? An Echo That Continues to Vibrate.

The health risks to humans and non-human biota exposed to low dose ionizing radiation remain ambiguous and are the subject of intense debate. The need to establish risk assessment standards based on the mechanisms underlying low-level radiation exposure has been recognized by regulatory agencies as critical to adequately protect people and to make the most effective use of national resources. Here, the authors briefly review evidence showing that the molecular and biochemical changes induced by low doses of radiation differ from those induced by high doses. In particular, an array of redundant and inter-related mechanisms act in both prokaryotes and eukaryotes to restore DNA integrity following exposures to relatively low doses of sparsely ionizing radiation. Furthermore, the radiation-induced protective mechanisms often overcompensate and minimize the mutagenic potential of the byproducts of normal oxidative metabolism. In contrast to adaptive protection observed at low doses of sparsely ionizing radiation, there is evidence that even a single nuclear traversal by a densely ionizing particle track can trigger harmful effects that spread beyond the traversed cell and induce damaging effects in the nearby bystander cells. In vivo studies examining whether exposure to low dose radiation at younger age modulates the latency of expression of age-related diseases such as cancer, together with studies on the role of genetic susceptibility, will further illuminate the magnitude of risk of exposure to low dose radiation.

The advantage of antibody cocktails for targeted alpha therapy depends on specific activity.

UNLABELLED: Nonuniform dose distributions among disseminated tumor cells can be a significant limiting factor in targeted α therapy. This study examines how cocktails of radiolabeled antibodies can be formulated to overcome this limitation. METHODS: Cultured MDA-MB-231 human breast cancer cells were treated with different concentrations of a cocktail of 4 fluorochrome-conjugated monoclonal antibodies. The amount of each antibody bound to each cell was quantified using flow cytometry. A spreadsheet was developed to "arm" the antibodies with any desired radionuclide and specific activity, calculate the absorbed dose to each cell, and perform a Monte Carlo simulation of the surviving fraction of cells after exposure to cocktails of different antibody combinations. Simulations were performed for the α-particle emitters (211)At, (213)Bi, and (225)Ac. RESULTS: Activity delivered to the least labeled cell can be increased by 200%-400% with antibody cocktails, relative to the best-performing single antibody. Specific activity determined whether a cocktail or a single antibody achieved greater cell killing. With certain specific activities, cocktails outperformed single antibodies by a factor of up to 244. There was a profound difference (≤16 logs) in the surviving fraction when a uniform antibody distribution was assumed and compared with the experimentally observed nonuniform distribution. CONCLUSION: These findings suggest that targeted α therapy can be improved with customized radiolabeled antibody cocktails. Depending on the antibody combination and specific activity of the radiolabeled antibodies, cocktails can provide a substantial advantage in tumor cell killing. The methodology used in this analysis provides a foundation for pretreatment prediction of tumor cell survival in the context of personalized cancer therapy.

Dab1 is required for synaptic plasticity and associative learning.

Disabled-1 (Dab1) is an adaptor protein that is an obligate effector of the Reelin signaling pathway, and is critical for neuronal migration and dendrite outgrowth during development. Components of the Reelin pathway are highly expressed during development, but also continue to be expressed in the adult brain. Here we investigated in detail the expression pattern of Dab1 in the postnatal and adult forebrain, and determined that it is expressed in excitatory as well as inhibitory neurons. Dab1 was found to be localized in different cellular compartments, including the soma, dendrites, presynaptic and postsynaptic structures. Mice that are deficient in Dab1, Reelin, or the Reelin receptors ApoER2 and VLDLR exhibit severely perturbed brain cytoarchitecture, limiting the utility of these mice for investigating the role of this signaling pathway in the adult brain. In this study, we developed an adult forebrain-specific and excitatory neuron-specific conditional knock-out mouse line, and demonstrated that Dab1 is a critical regulator of synaptic function and hippocampal-dependent associative and spatial learning. These dramatic abnormalities were accompanied by a reduction in dendritic spine size, and defects in basal and plasticity-induced Akt and ERK1/2 signaling. Deletion of Dab1 led to no obvious changes in neuronal positioning, dendrite morphology, spine density, or synaptic composition. Collectively, these data conclusively demonstrate an important role for Reelin-Dab1 signaling in the adult forebrain, and underscore the importance of this pathway in learning and memory.

Dyrk1A overexpression inhibits proliferation and induces premature neuronal differentiation of neural progenitor cells.

Dyrk1A is a member of the mammalian Dyrk [dual-specificity tyrosine-(Y)-phosphorylation regulated kinase] family of protein kinases that is expressed at high levels in the brain, but its role in the development and function of this organ is not well understood. The human DYRK1A gene is located on trisomic chromosome 21 in Down syndrome (DS) patients, leading to its overexpression. Dyrk1A is also overexpressed in animal models of DS and in gene-specific transgenic mice that consistently exhibit cognitive impairment. To elucidate the cellular and molecular mechanisms that are affected by increased levels of Dyrk1A in the developing brain, we overexpressed this kinase in the embryonic mouse neocortex using the in utero electroporation technique. We found that Dyrk1A overexpression inhibits neural cell proliferation and promotes premature neuronal differentiation in the developing cerebral cortex without affecting cell fate and layer positioning. These effects are dependent on the Dyrk1A kinase activity and are mediated by the nuclear export and degradation of cyclin D1. This study identifies specific Dyrk1A-induced mechanisms that disrupt the normal process of corticogenesis and possibly contribute to cognitive impairment observed in DS patients and animal models.

Pharmacological profile of the thyroid hormone receptor antagonist NH3 in rats.

NH3 is a thyroid hormone receptor (TR) antagonist that inhibits binding of thyroid hormones to their receptor and that inhibits cofactor recruitment. It was active in a tadpole tail resorption assay, with partial agonist activity at high concentrations. We determined the effect of NH3 on the cholesterol-lowering, thyroid stimulating hormone (TSH)-lowering, and tachycardic action of thyroid hormone (T(3)) in rats. Cholesterol-fed, euthyroid rats were treated for 7 days with NH3, and a dose response (46.2-27,700 nmol/kg/day) was determined. We also determined the effect of two doses of T(3) on the NH3 dose-response curve. NH3 decreased heart rate modestly starting at 46.2 nmol/kg/day, but the effect was lost at >2920 nmol/kg/day. At 27,700 nmol/kg/day, tachycardia was seen, suggesting partial agonist activity. NH3 increased plasma cholesterol to a maximum of 27% at 462 nmol/kg/day. At higher doses, cholesterol was reduced, suggesting partial agonist activity. Plasma TSH was increased from 46.2 to 462 nmol/kg/day NH3, but at higher doses, this effect was lost, and partial agonist effects were apparent. T(3) at 15.4 and 46.2 nmol/kg/day increased heart rate, reduced cholesterol, and reduced plasma TSH. NH3 inhibited the cholesterol-lowering, TSH-lowering and tachycardic effects of 15.4 nmol/kg/day T(3), but much of the effect was lost at >924 nmol/kg/day doses. NH3 had no effect on the cholesterol-lowering action of 46.2 nmol/kg/day T(3), but it inhibited the tachycardic and TSH suppressant effects up to the 924 nmol/kg/day dose. Single doses of 462 and 27,700 nmol/kg caused no TR inhibitory effects. In conclusion, NH3 has TR antagonist properties on T(3)-responsive parameters, but it has partial agonist properties at higher doses.