OBJECTIVE: Onychomatricoma (OM), an uncommon benign fibroepithelial neoplasm of the nail unit, is sometimes diagnostically challenging for clinicians and pathologists. OM consistently expresses CD34, but no specific immunohistohemical markers or recurrent genetic alterations have been identified to date. Recent studies have suggested that Wnt signalling is a key molecular characteristic of OM.
RESULTS: Ten cases were analysed: four classical OM including two with pleomorphic cells; two superficial acral fibromyxoma-like variants of OM; three micropapilliferum variants of OM including one with pleomorphic cells; and one proliferating variant of OM. Immunohistochemically, the spindle cells were positive with CD34 (n = 10) and CD99 (n = 1), with focal reactivity for CD10 (n = 5). The epithelial component of the tumours expressed immunopositivity for LEF-1. Using array comparative genomic hybridization (aCGH), we demonstrated that all OM, including its variants that were tested (n = 8), harboured a few copy number alterations with losses of whole or part of chromosome 13 including the RB1 gene (n = 8) and chromosome 16 (n = 6).
CONCLUSIONS: We report a recurrent loss of RB1 (13q) as a possible driver molecular event in OM indicating a relationship between OM and other lesions of the spectrum of the so-called \'13q/RB1\' family of tumours. We did not identify a role for the Wnt/beta-catenin signalling pathway, as has been proposed in a recent study. LEF-1 could be a potential sensitive and specific marker of OM and should be used in the differential diagnosis between OM, superficial acral fibromyxoma, and the CD34-positive fibrosing family of tumours.

Neuroendocrine carcinomas (NEC) are aggressive malignant diseases. Etoposide-based rechallenge (EBR) and the prognostic role of RB transcriptional corepressor 1 (RB1) status in second-line chemotherapy (2L) have not been studied. The objectives of this study were to report the results of 2L including EBR as well as prognostic factors in a national retrospective multicentre study. NEC patients treated with 2L and further, with tissue samples available, were included. RB1 status and morphological classification were reviewed centrally. Among the 121 NEC patients (40% female, median age 61 years) included, there were 73 small-cell NEC (60%), 34 large-cell NEC (28%) and 14 NEC (not otherwise specified, 12%). Primary sites were lung (39%), gastroenteropancreatic (36%), other (13%) and unknown (12%). Median Ki-67 index was 80%. Median progression-free survival (PFS) and overall survival (OS) under 2L were 2.1 and 6.2 months, respectively. No difference was observed between patients who received an \'adenocarcinoma-like\' or a \'neuroendocrine-like\' 2L or according to the RB1 status. Thoracic NEC primary was the only adverse prognostic factor for OS. EBR, administered to 31 patients, resulted in a 62% disease control rate with a median PFS and OS of 3.2 and 11.7 months, respectively. In the 94 patients with a relapse-free interval of ≥3 months after first-line platinum-etoposide chemotherapy, the median OS was 12 months in patients who received EBR as compared to 5.9 months in patients who did not (P = 0.043). EBR could be the best 2L option for patient with initial response to first-line platinum-etoposide lasting at least 3 months. RB1 status does not provide prognostic information in this setting.

BACKGROUND: Survivors with heritable retinoblastoma (RB) face a high risk for second primary cancer and RB in their children. Knowledge of heredity can support second cancer surveillance, convey reproductive options or early diagnosis of RB in their offspring. Currently, all newly diagnosed Danish patients with RB are offered genetic testing, as opposed to a minority of survivors diagnosed before available DNA testing.
OBJECTIVE: To examine RB survivors\' response to unsolicited contact, uptake of genetic testing, and RB1 variant detection rate, and to qualitatively evaluate the experience and overall impact of genetic testing for heritable RB.
METHODS: Genetically untested adult RB survivors were invited to receive genetic counseling, undergo genetic testing for heritable RB and complete an eye examination. The number of responses, uptake of genetic testing and genetic results are descriptively reported. Additionally, responding survivors participated in a qualitative interview study of the perceived impact of genetic testing. Interviews were audio-recorded, transcribed verbatim and thematically analyzed.
RESULTS: Among invited RB survivors, 58% responded. Of these, 88% opted for genetic counseling and genetic testing. A diagnosis of heritable RB was established in 23% of RB survivors. Interestingly, all of these survivors were unilaterally affected. Analysis of data from the interviews revealed three recurring themes regarding the impact of genetic counseling and testing several years after initial diagnosis: \'Risk of what?\', \'Knowledge is important\' and \'Impact of the result\'. The possible risk ofsecond cancer and RB in their children was new knowledge for several participants; however, in general, the participants appreciated receiving genetic information and certainty about heredity. Accordingly, the impact of genetic counseling and testing was perceived in a positive way.
CONCLUSIONS: Overall, RB survivors valued the opportunity to receive genetic counseling and undergo genetic testing many years after diagnosis. Responding RB survivors appreciated the invitation to test, felt well-informed and described little decisional conflict regarding their decision-making, valuing the genetic information and certainty. Heritable RB was confirmed in 23% of the previously untested RB survivors. These individuals emphasized the value of knowing and being proactive regarding both reproduction and cancer risk.

OBJECTIVE: Large-cell neuroendocrine carcinoma (LCNEC) and small-cell carcinoma (SCLC) of lung encompass high-grade neuroendocrine tumour category and share several fundamental features. As both tumours may respond to different treatment modalities and show unique molecular alterations distinction between the two is clinically relevant, but can be challenging due to sampling and fixation issues and shared morphological features.
METHODS: Surgically resected primary SCLC (n = 129) and LCNEC (n = 27) were immunohistochemically stained with Rb1, cyclin D1 and p16 using tissue microarray (TMA), and expression patterns of the proteins were compared between the two to identify the discriminatory pattern.
RESULTS: All markers had high diagnostic accuracy; Rb1 was the highest followed by p16 and cyclin D1. The majority of SCLC had the pattern Rb1-/p16+/cyclin D1- and more than half of LCNEC had Rb1+/p16-/cyclin D1+. Overall, the expression pattern Rb1- and cyclin D1- was strongly associated with the diagnosis of SCLC, while the pattern Rb1+ and/or cyclin D1+ was strongly associated with LCNEC. The use of this simplified expression pattern leads to a diagnostic accuracy of 97.3%. p16 did not add to further discrimination. The heterogeneity in Rb1, cyclin D1 and p16 expression was insignificant in SCLCs compared with LCNECs.
CONCLUSIONS: Use of Rb1, cyclin D1 and p16 immunohistochemistry can distinguish the two with high accuracy. Notably, the Rb1-/cyclin D1- pattern in given tumour sample would confirm the diagnosis of SCLC. Our results could be extrapolated and applied to routine diagnostic samples such as biopsies and cytology samples.

Retinoblastoma (Rb) is the most common primary intraocular childhood malignancy and one of the main causes of blindness in children. In China, most tumors are diagnosed at an advanced stage and have relatively poor outcomes compared to developed countries. Here, we aimed to update the clinical manifestations and RB transcriptional corepressor 1 (RB1) mutation spectrum in Chinese Rb patients. Medical charts of 184 eyes in 145 Chinese Rb patients belonging to unrelated families were reviewed. Genomic DNA was isolated from peripheral blood of the patients and their parents. Mutation analysis of whole coding regions, promoter regions and flanking splice sites in the RB1 gene was performed. In addition, multiplex ligation-dependent probe amplification (MLPA) was done to detect gross aberrations. Germline RB1 mutations were observed in 37.2% (54/145) of Rb patients. RB1-mutated patients presented with earlier age of diagnosis (p = 0.019), with a significantly larger proportion of bilateral cases (p = <0.001) and secondary malignancies (p = 0.027) relative to those without RB1 mutations. For ocular clinical presentations, RB1-mutated retinoblastomas presented with a larger proportion of ectropion uveae (p = 0.017) and iris neovascularization (p = 0.001). These RB1 mutations comprised of 13 (24.1%) nonsense mutation, 13 (24.1%) splicing mutations, 11 (20.4%) frameshift deletions, 11 (20.4%) gross mutations, 3 (5.6%) missense mutations, 2 (3.7%) promoter mutations and 1 (1.9%) non-frameshift deletion. In addition, 8 novel RB1 mutations were identified. These germline RB1 mutations were not related to age at diagnosis or laterality. Here, we provide a comprehensive spectrum of RB1 germline mutations in Chinese Rb patients and describe correlations between RB1 mutations and clinical presentations. Our study also provides new evidence that will inform management and genetic counselling of Rb patients and families.

BACKGROUND: Androgen deprivation therapy (ADT) has remained the first line strategy for treatment of advanced prostate cancers. Despite the profound efficacy of ADT in preventing clinical remission, 30-50% of advanced prostate cancer will develop resistance to hormonal deprivation therapy. This study aimed to evaluate the potential role of RB1 and TP53 expressions as biomarkers for predicting time to castration-resistant prostate cancer (CRPC).
METHODS: The clinical and pathological data of patients with prostate cancer were collected retrospectively from Dr. Sardjito General Hospital, Yogyakarta. Between 2015 and 2019, a total of 36 patients who received castration were included. Expressions of mRNA of RB1 and TP53 from primary tumors were quantified using quantitative Real Time Polymerase Chain Reaction (qRT-PCR).
RESULTS: The expressions of mRNA of RB1 and TP53 increased in prostate cancer tissues compared to hyperplastic prostates and significantly downregulated in metastatic prostate cancers (p < 0.001). Lower mRNA TP53 expression correlated with shorter time to CRPC among patients treated with ADT (p = 0.006). In addition, stratified analysis showed that lower mRNA RB1 expression was significantly associated with shorter CRPC both in metastatic (p = 0.017) and non-metastatic (p = 0.001) prostate cancer patients.
CONCLUSIONS: Low expression of mRNA of RB1 and TP53 has been shown to be a potential marker of shorter time to develop CRPC in patients with advanced stages of prostate cancer treated with ADT. Meanwhile, ISUP score >4 were not shown predictive value on time to CRPC.

It has increasingly been considered crucial the understanding of DNA methylation of Tumor Suppressor Gene (TSG) promoters, such as that of retinoblastoma 1 gene (RB1), and its role during carcinogenesis. We present a detailed and optimized protocol of the methylation-specific PCR (MSP) technique to study RB1 gene promoter hypermethylation.

Superficial acral fibromyxoma (SAF) is an uncommon benign dermal mesenchymal lesion of adults with predilection for acral sites, in particular the nail region. To date, less than 300 cases have been reported. SAFs consistently express CD34, but other diagnostic markers or specific genetic alterations have not been established yet. We describe 11 SAFs occurring in 7 men and 4 women aged 37 to 86years (median, 48 years). Mean size was 6mm (range, 4-20mm). Affected sites were fingers (n=5), toes (n=3), heel (n=1), calf (n=1), and unspecified digit (n=1). None of 10 patients with available follow-up (2-60months; median, 24months) developed recurrence. Histology showed relatively hypocellular vaguely lobulated nodules composed of bland-looking spindled or stellate fibroblast-like cells arranged into storiform or loose fascicles within a variably myxoid, fibromyxoid, or collagenous vascularized stroma. Immunohistochemistry showed expression of CD34 (9/10) and focal weak reactivity for epithelial membrane antigen (2/11). None of the lesions expressed protein S100 (0/11), MUC4 (0/11), or STAT6 (0/11). Loss of Rb1 immunoexpression was observed in 9 (90%) of 10 cases. All 7 cases with successful RB1 fluorescence in situ hybridization testing showed RB1 gene deletions, which was variably associated with co-loss of the corresponding 13q12 signal (monosomy at the 13q region). To our knowledge, this is the first study investigating the expression status of the tumor suppressor Rb1 in SAF by immunohistochemistry and fluorescence in situ hybridization. Our results showed frequent Rb1 deficiency as a possible driver molecular event in SAF (seen in 90% of cases) indicating relationship of SAF to the RB1-deleted tumor family.

Trihalomethanes (THM) are undesired disinfection byproducts (DBPs) formed during water treatment. Mice exposed to DBPs showed global DNA hypomethylation and c-myc and c-jun gene-specific hypomethylation, while evidence of epigenetic effects in humans is scarce. We explored the association between lifetime THM exposure and DNA methylation through an epigenome-wide association study. We selected 138 population-based controls from a case-control study of colorectal cancer conducted in Barcelona, Spain, exposed to average lifetime THM levels ≤85 μg/L vs. >85 μg/L (N = 68 and N = 70, respectively). Mean age of participants was 70 years, and 54% were male. Average lifetime THM level in the exposure groups was 64 and 130 µg/L, respectively. DNA was extracted from whole blood and was bisulphite converted to measure DNA methylation levels using the Illumina HumanMethylation450 BeadChip. Data preprocessing was performed using RnBeads. Methylation was compared between exposure groups using empirical Bayes moderated linear regression for CpG sites and Gaussian kernel for CpG regions. ConsensusPathDB was used for gene set enrichment. Statistically significant differences in methylation between exposure groups was found in 140 CpG sites and 30 gene-related regions, after false discovery rate <0.05 and adjustment for age, sex, methylation first principal component, and blood cell proportion. The annotated genes were localized to several cancer pathways. Among them, 29 CpGs had methylation levels associated with THM levels (|Δβ|≥0.05) located in 11 genes associated with cancer in other studies. Our results suggest that THM exposure may affect DNA methylation in genes related to tumors, including colorectal and bladder cancers. Future confirmation studies are required.