Widening the spectrum of Lynch syndrome: first report of testicular seminoma attributable to MSH2 loss

Familial syndromes associated with testicular and paratesticular neoplasms: a comprehensive review

A syndromic association between a subset of testicular/paratesticular neoplasms is well established. Such examples include Carney complex and large cell calcifying Sertoli cell tumor, Peutz-Jeghers syndrome and intratubular large cell hyalinizing Sertoli cell neoplasia, and VHL syndrome and clear cell papillary cystadenoma of the epididymis.However, recent studies proposed potential novel links between some testicular and paratesticular neoplasms with certain tumor syndromes. While more studies are still needed to solidify these associations, recent research suggests that a subset of Leydig cell tumors may arise in patients with hereditary leiomyomatosis and renal cell carcinoma syndrome or that some seminomas may occur in Lynch syndrome patients. Additionally, an association between testicular sex cord stromal tumors and paratesticular sarcomas with Familial adenomatous polyposis syndrome and DICER1 syndrome, respectively, has been proposed as well. This review provides a comprehensive overview of the intricate relationship between familial syndromes and associated testicular and paratesticular tumors, shedding light on their clinicopathological and molecular characteristics.

Gender-specific counselling of patients with upper tract urothelial carcinoma and Lynch syndrome

PURPOSE

Lynch syndrome (LS) is an autosomal dominant genetic syndrome resulting in a wide spectrum of malignancies caused by germline mutations in mismatch repair genes (MMR). Gene mutations have different effects and penetrance between the two genders. The aim of this review is to offer a gender-specific evidence-based clinical guide on diagnosis, screening, surveillance, and counselling of UTUC patients with LS.

METHODS

Using MEDLINE, a non-systematic review was performed including articles between 2004 and 2022. English language original articles, reviews, and editorials were selected based on their clinical relevance.

RESULTS

Upper tract urothelial carcinoma (UTUC) is the third most common malignancy in Lynch syndrome. Up to 21% of new UTUC cases may have unrecognized LS as the underlying cause. LS-UTUC does not have a clear gender prevalence, even if it seems to slightly prefer the male gender. The MSH6 variant is significantly associated with female gender (p < 0.001) and with gynecological malignancies. Female MSH2 and MLH1 carriers have higher rates for endometrial and ovarian cancer with respect to the general population, while male MSH2 and MLH1 carriers have, respectively, higher rate of prostate cancer and upper GI tract, or biliary or pancreatic cancers. Conflicting evidence remains on the association of testicular cancer with LS.

CONCLUSION

LS is a polyhedric disease, having a great impact on patients and their families that requires a multidisciplinary approach. UTUC patients should be systematically screened for LS, and urologists have to be aware that the same MMR mutation may lead to different malignancies according to the patient's gender.

Genomic instability and the link to infertility: A focus on microsatellites and genomic instability syndromes

Infertility is associated to multiple types of different genomic instabilities and is a genetic feature of genomic instability syndromes. While the mismatch repair machinery contributes to the maintenance of genome integrity, surprisingly its potential role in infertility is overlooked. Defects in mismatch repair mechanisms contribute to microsatellite instability and genomic instability syndromes, due to the inability to repair newly replicated DNA. This article reviews the literature to date to elucidate the contribution of microsatellite instability to genomic instability syndromes and infertility. The key findings presented reveal microsatellite instability is poorly researched in genomic instability syndromes and infertility.

Mismatch repair deficiency occurs very rarely in seminomas

Background

Dense tumor-associated lymphocyte infiltration is linked to mismatch repair (MMR) deficiency in colorectal and endometrial cancer. MMR deficiency is of high clinical importance as MMR deficient cancers tend to react favorably to treatment with immune checkpoint inhibitors. Strong lymphocytic infiltration is a morphological hallmark of seminomas. We thus asked whether seminomas may exhibit MMR deficiency at relevant frequency.

Methods

To screen for tumors with MMR deficiency, protein expression of MLH1, PMS2, MSH2, and MSH6 was analyzed by immunohistochemistry (IHC) on a tissue microarray (TMA) containing 574 seminomas.

Results

In total, 536 cases were evaluable resulting in 481 seminomas with unequivocally intact MMR protein expression. In 55 cancers, one or several IHC stains were equivocal and lacked detectable MMR protein in both tumor and stromal cells. Large section IHC analysis of all 55 equivocal cases demonstrated substantial staining issues due to improper fixation in 54 cases and identified one tumor with clear-cut MLH1 and PMS2 protein loss. This seminoma showed homogeneous loss of MLH1 and PMS2 in the entire tumor mass whereas minor adjacent foci of associated germ cell neoplasia in situ (GCNIS) were MMR intact. Polymerase chain reaction (PCR) analysis using the 5 microsatellite loci of the “Bethesda Panel” revealed instability in 1 of 4 interpretable loci (“MSI-low”) and additional instability of the complex tetra-penta repeat locus MYCL1 in this tumor.

Conclusions

In summary, one single seminoma with MMR deficiency, characterized by protein loss of MLH1 and PMS2, was identified among 536 interpretable seminomas (0.19%). MMR deficiency is not a relevant determinant of lymphocyte influx in seminoma.

Cisplatin Resistance in Testicular Germ Cell Tumors: Current Challenges from Various Perspectives

Testicular germ cell tumors share a marked sensitivity to cisplatin, contributing to their overall good prognosis. However, a subset of patients develop resistance to platinum-based treatments, by still-elusive mechanisms, experiencing poor quality of life due to multiple (often ineffective) interventions and, eventually, dying from disease. Currently, there is a lack of defined treatment opportunities for these patients that tackle the mechanism(s) underlying the emergence of resistance. Herein, we aim to provide a multifaceted overview of cisplatin resistance in testicular germ cell tumors, from the clinical perspective, to the pathobiology (including mechanisms contributing to induction of the resistant phenotype), to experimental models available for studying this occurrence. We provide a systematic summary of pre-target, on-target, post-target, and off-target mechanisms putatively involved in cisplatin resistance, providing data from preclinical studies and from those attempting validation in clinical samples, including those exploring specific alterations as therapeutic targets, some of them included in ongoing clinical trials. We briefly discuss the specificities of resistance related to teratoma (differentiated) phenotype, including the phenomena of growing teratoma syndrome and development of somatic-type malignancy. Cisplatin resistance is most likely multifactorial, and a combination of therapeutic strategies will most likely produce the best clinical benefit.

Detailed Characterization of Immune Cell Infiltrate and Expression of Immune Checkpoint Molecules PD-L1/CTLA-4 and MMR Proteins in Testicular Germ Cell Tumors Disclose Novel Disease Biomarkers

Background: The immune infiltrate plays an important part in testicular germ cell tumors, but it remains scarcely studied. We aimed at thoroughly characterizing the immune infiltrate and expression of immune checkpoints PD-L1/CTLA-4 and mismatch repair (MMR) proteins in these neoplasms, seeking for associations with patient outcome. Methods: A total of 162 consecutively diagnosed patients (2005-2018) were included. Immunostaining for PD-L1, CTLA-4 and MMR proteins was independently assessed both in immune cells (ICs) and tumor cells (TCs) of primary tumors and metastases, and characterization of IC populations was pursued. Results: PD-L1 and CTLA-4 positivity in ICs was frequent (85.5% and 96.3%). Patients with absent PD-L1 positive ICs exhibited significantly worse relapse-free survival (hazard ratio = 4.481, 95% CI 1.366-14.697, p = 0.013), both in univariable and multivariable analysis. Lower CD20 and CD3 IC infiltration in seminomas associated with higher disease stage (p = 0.0216, p = 0.0291). CTLA-4 TC intensity was significantly higher in yolk sac tumor, choriocarcinoma and teratoma, while PD-L1 TC positivity was significantly more frequent in choriocarcinoma. Both PD-L1 and CTLA-4 immunoexpression in ICs of metastatic samples was frequent (100% and 88.2%). MMR proteins were differentially expressed among the different tumor subtypes. Conclusions: Immune infiltrate/checkpoints associate with patients' outcome, constituting novel (potentially targetable) disease biomarkers.