The role of cremaster muscle in testicular descent in humans and animal models.

Testicular descent is a complex developmental process involving anatomical and hormonal regulation. The gubernaculum undergoes a "swelling reaction" during the transabdominal phase and is mainly under the control of Insulin-Like Peptide 3 (INSL-3) and Mullerian Inhibitory Substance/Anti-Mullerian Hormone (MIS/AMH). The second phase of testicular descent is regulated by androgens and calcitonin gene-related peptide (CGRP) release from the sensory nucleus of the genitofemoral nerve (GFN). In rodents, the active proliferation of the gubernacular tip and cremaster muscle, its rhythmic contraction, as well as the chemotactic gradient provided by the CGRP result in eventual migration of the testis into the scrotum. This review illustrates the structural aspects and hormonal control of cremaster muscle development to better understand the mechanism of testicular descent in normal rodents and humans, compared to diseased rodent models. The analysis showed the cremaster muscle is formed from mesenchymal differentiation of the gubernacular tip and is not a direct passive extension of internal oblique muscle. Cremaster muscle matures slower than other body muscles, and the persistence of immature myogenic proteins seen in cardiac muscle allows rhythmic contraction to guide the testis into the scrotum. Finally, remodelling of the cremaster muscle enables gubernacular eversion. Further understanding of the molecular regulators governing the structural and hormonal changes in the cremaster muscle may lead to new advances in the treatment of undescended testes.

Impact of Radiotherapy on the Efficacy and Toxicity of anti-PD-1 Inhibitors in Metastatic NSCLC.

BACKGROUND: The impact of radiotherapy (RT) on the efficacy and toxicity of immune checkpoint inhibitors (ICIs) in patients with metastatic non-small-cell lung cancer (NSCLC) is unclear. MATERIALS AND METHODS: We identified patients with metastatic NSCLC treated with the anti-programmed death 1 antibodies nivolumab or pembrolizumab between January 2016 and May 2019 at 3 tertiary centers, who were also treated with palliative RT either during or within 3 months of starting anti-programmed death 1 treatment. Patient demographics, tumor characteristics, and treatment history were collected. Response rates, progression-free survival (PFS), and overall survival (OS) were analyzed and correlated with RT use. RESULTS: A total of 269 patients were identified, with a median follow-up of 19.4 months. The median age was 70 years (range, 35-90 years), and they were 63% male, 60% smokers, and 65% had adenocarcinoma histology. At the commencement of ICI treatment, the majority (86%) had ≥ 1 line of prior therapy and 34% had brain metastases. A total of 102 (38%) patients received RT within 3 months of starting ICI or subsequently during ICI treatment. Of patients that received RT, 86 (84%) received conventional hypofractionated RT, and, in the majority, 81 (79%) the intent of RT was symptom control. The use of RT did not increase grade 3/4 immune-related adverse events. The overall median PFS was 2.0 months (95% confidence interval, 1.3-2.6 months) and the median OS was 9.0 months (95% confidence interval, 6.4-9.5 months). There were no significant differences in median PFS (3.0 vs. 2.0 months; P = .515) and median OS (9.0 vs. 9.0 months; P = .917) in the patients who received RT versus those that did not. CONCLUSIONS: In patients with metastatic NSCLC, the addition of RT to ICI was not associated with increased toxicity or improved survival.

Nivolumab resulting in persistently elevated troponin levels despite clinical remission of myocarditis and myositis in a patient with malignant pleural mesothelioma: case report.

Malignant pleural mesothelioma (MPM) remains a deadly disease with limited therapeutic options beyond platinum/pemetrexed chemotherapy. Immune checkpoint inhibitors have demonstrated modest benefit in the second to later-line settings. An MPM patient from our institute developed myocarditis and myositis after 2 cycles of second-line nivolumab. Despite immunosuppression with corticosteroids and mycophenolate mofetil, there was ongoing rise in troponin levels which remained elevated for months. The patient developed an impressive but brief response following cessation of nivolumab. Myocarditis and myositis are rare complications of immune checkpoint inhibitors. Clinicians should be aware of these possible complications as myocarditis can result in mortality.

The regulation of testicular descent and the effects of cryptorchidism.

The first half of this review examines the boundary between endocrinology and embryonic development, with the aim of highlighting the way hormones and signaling systems regulate the complex morphological changes to enable the intra-abdominal fetal testes to reach the scrotum. The genitoinguinal ligament, or gubernaculum, first enlarges to hold the testis near the groin, and then it develops limb-bud-like properties and migrates across the pubic region to reach the scrotum. Recent advances show key roles for insulin-like hormone 3 in the first step, with androgen and the genitofemoral nerve involved in the second step. The mammary line may also be involved in initiating the migration. The key events in early postnatal germ cell development are then reviewed because there is mounting evidence for this to be crucial in preventing infertility and malignancy later in life. We review the recent advances in what is known about the etiology of cryptorchidism and summarize the syndromes where a specific molecular cause has been found. Finally, we cover the recent literature on timing of surgery, the issues around acquired cryptorchidism, and the limited role of hormone therapy. We conclude with some observations about the differences between animal models and baby boys with cryptorchidism.