Loss of heterozygosity on chromosomes 10 and 17 in clinically localized prostate carcinoma

Loss of heterozygosity (LOH) at chromosomal loci has been associated with the presence of tumor suppressor genes at the deleted loci. Twenty-six clinically localized, Stage B prostate carcinomas were analyzed for LOH on chromosomes 10 and 17 using microsatellite markers. Two of 26 carcinomas showed LOH on 17p while one showed LOH on 17q. Chromosome 10 showed a complex pattern of LOH with monosomy (1 case), LOH on 10p (1 case), proximal 10q (1 case) and distal 10q (2 cases). Overall 29% of informative cases showed LOH on chromosome 10. These results are consistent with the presence of a tumor suppressor for prostate cancer on 17p and multiple tumor suppressor genes on chromosome 10. © 1996 Wiley-Liss, Inc.     

Mixed Exocrine-Neuroendocrine Carcinoma of the Nasal Cavity: Clinico-Pathologic and Molecular Study of a Case and Review of the Literature

Sinonasal intestinal-type adenocarcinomas (ITACs) are rare neoplasms histologically resembling intestinal adenocarcinomas. Although a neuroendocrine differentiation in ITACs has been described, true mixed exocrine-neuroendocrine carcinomas, neoplasms in which each component represents at least 30 % of the lesion, are extremely rare and their molecular alterations are largely unknown. We describe herein the clinico-pathologic features, the methylation profile, chromosomal gains and losses, and mutation analysis of KRAS, BRAF and p53 in a nasal mixed exocrine-neuroendocrine carcinoma resected in a 79-year-old man. The tumor was composed of an ITAC and a poorly differentiated neuroendocrine carcinoma. Both exocrine and neuroendocrine components were CK8, CK20, CDX2 and p53 positive, and CK7 and TTF1 negative. The neuroendocrine component also showed immunoreactivity for chromogranin A, synaptophysin, serotonin and glicentin. Gains and losses were found at following chromosome regions: 17p13 (TP53), 14q24 (MLH3), 19q13 (KLK3), 5q21 (APC), 7q21 (CDK6), 9q34 (DAPK1), 12p13 (TNFRSF 1A, CDKN1B), 13q12 (BRCA2), 17p13.3 (HIC1), 18q21 (BCL2), and 22q12 (TIMP3). Aberrant methylation was detected only in the neuroendocrine component and involved APC and DAPK1 genes. No mutation of KRAS (exons 2–4), BRAF (exon 15), and p53 (exons 4–10) was found in both components. The results suggest a monoclonal origin of the tumor from a pluripotent cell undergoing a biphenotypic differentiation and that the neuroendocrine differentiation may be from an exocrine to an endocrine pathway. We have also reviewed the literature on sinonasal mixed exocrine-neuroendocrine carcinomas to give to the reader a comprehensive overview of these very rare tumor types.     

Differential Chromosome Allelic Imbalance in the Progression of Human Prostate Cancer

Purpose

It is widely accepted that an accumulation of genetic alterations plays an important role in the genesis of human cancers. We wished to obtain a comprehensive view of the role of genetic changes in prostate cancer.

Materials and Methods

We screened 42 primary prostate tumors for allelic imbalance (AI) on 8 autosomal chromosome arms of interest (5q, 7q, 8p, 10q, 13q, 16q, 17q, 18q) by using 2 DNA probes for restriction fragment length polymorphism (RFLP) and 19 microsatellite markers (CA repeats).

Results

The most frequent allelic imbalances were observed on 8p (58 percent) and 16q (53 percent). AI exceeding 20 percent was also observed at sites on chromosome arms 7q (46 percent), 10q (23 percent), 13q (26 percent), 17q (34 percent) and 18q (39 percent), whereas AI was infrequent on 5q (10 percent).

Conclusions

The data indicate that a relatively large number of chromosome loci play a part in the etiology and progression of this tumor type. Moreover, our findings suggest that inactivation of a putative tumor suppressor gene on 7q and 13q is an early event in prostate tumorigenesis. In contrast, the close link between an invasive phenotype and AI on 10q and 18q suggests that these genetic alterations occur late in prostate tumorigenesis.     

Discovery of new DNA amplification loci in prostate cancer by comparative genomic hybridization

BACKGROUND: DNA sequence amplifications are involved in the progression of many tumor types, and have also been found in advanced prostate cancer. The aim of this study was to detect new loci of DNA amplifications in prostate cancer. METHODS: Comparative genomic hybridization (CGH) was used for whole genome screening of DNA sequence copy number alterations in 27 advanced prostate cancers. RESULTS: The most prevalent changes were losses of 8p, 13q (52%, each), 6q (48%), 18q (37%), 5q (30%), 2q, 4q and 16q (26%, each), and gains of 8q (48%), Xq (40%), and Xp (26%). In addition, 16 high-level amplifications were found. These included Xq12 (five), 8q24 (two), and 11q13 (one) with known putative target genes (androgen receptor, MYC and Cyclin D1), and 1q21-25 (three), 10q22 (two), 17q23-24 (two), and 8q21 (one) where the target genes remain unknown. CONCLUSIONS: High-level amplifications at different chromosomal sites occur in advanced prostate cancer. The detection of amplified chromosomal regions may serve as a starting point to discover novel oncogenes involved in prostate cancer progression.     

睾丸肿瘤染色体杂合性丢失及微卫星不稳定性研究

目的　探讨睾丸肿瘤的发生、发展与微卫星不稳定性（ ＭＳＩ） 及染色体杂合性丢失（ＬＯＨ）的关系。　方法　利用ＰＣＲＭＩＡ技术,选用８ 种微卫星标记位点,分析２２ 例睾丸肿瘤ＬＯＨ及ＭＳＩ的变化。　结果　２２ 例中１４ 例出现ＬＯＨ（６４％ ）。定位于第９ 号染色体上的Ｄ９Ｓ６３ 位点的ＬＯＨ 发生率最高为４５％ ,次为第５ 号染色体上的ＡＰＣ位点（４３ ％） 及第１８ 号染色体上的ＤＣＣ位点（２５ ％） ;８ 例表现为ＭＳＩ（３６ ％） ,１７ 例表现为ＬＯＨ 或（ 和）ＭＳＩ,总阳性率为７７％ 。　结论　染色体９ｑ 及５ｑ 上存在的抑癌基因的失活以及微卫星不稳定性改变可能在睾丸肿瘤的发生发展中起重要作用。     

Loss of heterozygosity and microsatellite instability at chromosomal sites 1Q and 10Q in morphologically distinct regions of late stage prostate lesions

PURPOSE: We investigated the incidence of loss of heterozygosity (LOH) and microsatellite instability in sporadic prostate cancer and surrounding tissue at loci encompassing the HPC1 and PTEN genes. MATERIALS AND METHODS: Surgical specimens from 63 patients with sporadic stage T3 or T4 prostatic adenocarcinoma were analyzed for LOH and microsatellite instability. Microdissected tissue included morphologically normal foci, benign prostatic hyperplasia (BPH) and prostatic adenocarcinoma. LOH analysis was performed using 4 microsatellite markers that map in the region of the 1q24 to 25 locus of the putative prostate cancer susceptibility gene HPC1 and 4 that map in the region of the 10q23 locus of the PTEN gene. RESULTS: The incidence of LOH on 10q was consistent with that previously reported in prostatic tumors. LOH associated with the PTEN locus was recorded in morphologically normal foci, BPH and adenocarcinoma. Sequence analysis of PTEN in a limited number of lesions revealed mutations in nontumor and tumor tissue. Analysis of the DS10215 locus showed significant LOH in tumor but not in benign tissue, suggestive of a tumor suppressor gene in this region associated with prostatic neoplastic progression. In contrast, no significant LOH was observed in the same tissues at 4 loci on chromosome 1q. In this study we recorded elevated levels of microsatellite instability in benign prostatic tissue with an additional increase associated with prostatic adenocarcinoma. CONCLUSIONS: The low incidence of LOH in the region of the HPC1 locus in all prostate lesions studied suggests that this putative hereditary prostate cancer susceptibility locus does not appear to have a role in sporadic prostate cancer, at least not in the context of LOH. In contrast, analysis of the same tissues for LOH at chromosome 10q confirmed frequent alterations in this region linked to late stage prostate cancer. PTEN mutations in microdissected morphologically normal and BPH tissue showed alterations in nontumor tissue surrounding adenocarcinoma. Microsatellite instability was increased in adenocarcinomas over an elevated background recorded in surrounding tissues.     

Chromosomal changes in incidental prostatic carcinomas detected by comparative genomic hybridization

OBJECTIVES: The genetic changes underlying the development and progression of prostate cancer are poorly understood. To identify chromosomal regions in incidental prostatic carcinoma (T1a and T1b) was the primary aim of this study. MATERIALS AND METHODS: We used comparative genomic hybridization (CGH) to search for DNA sequence copy number changes on a series of 48 T1 prostate cancer diagnosed by transurethral resection (TURP) and by adenomectomy. Incidental prostatic carcinomas have not been studied by CGH previously. RESULTS: CGH analysis indicated that 14 cases (29.2%) of incidental prostatic carcinoma showed chromosome alterations. The most frequent alterations were chromosomal losses of 8p (10.4%), 13q (6.3%), 5q (4.2%) and 18q (4.2%), and gains of 17p (10.4%), 17q (10.4%), 9q (6.3%) and 7q (4.2%). Minimal overlapping chromosomal regions of loss, indicative for the presence of tumor suppressor genes (TSGs), were mapped to 8p22 and 13q14.1-q21.3, and minimal overlapping regions of gain, indicative for the presence of oncogenes, were found at 9q34.2-qter, 17p12 and 17q24-qter. The statistical analysis displayed a significant association between chromosomal aberration detected by CGH and high Gleason score (P < 0.005) as well as between tumor categories T1a and T1b and chromosomal imbalance (P = 0.041). CONCLUSIONS: Studies directed at incidental prostatic carcinomas allow discovery of chromosomal changes in small and highly malignant tumors. Our results suggest that loss or gain of DNA in these regions are important in prostate cancer. This is the first study, which documents the spectrum of chromosomal changes in incidental prostatic carcinomas.     

肝细胞癌微卫星不稳定和杂合性缺失分析

目的 通过检测肝细胞癌(hepatocellular carcinoma,HCC)微卫星不稳定（microsatellite instability,MSI)和杂合性缺失（loss of heterozygosity,LOH)发生频率,探讨上述遗传学改变与HCC临床病理的关系。方法 选择5个微卫星多态性标记对32例HCC进行了MSI与LOH分析。结果 32例HCC中有14例出现MSI,其中有6例出现2个位点MSI,后者癌肿转移率明显低于其他的组（P＝0．001）,在所检5个位点中D1S484和TP53 MSI发生频率最高,而D9S1604昨D8S555遗传学改变多为LOH且发生频率较低。结论 MSI是部分HCC发生、发展进程中一个重要的遗传改变,尤其在在无癌肿转移的肿瘤中。D1S484和TP53是HCC中对MSI敏感的检测位点。     

Genetic changes in stage pT2N0 prostate cancer studied by comparative genomic hybridization

OBJECTIVE: To identify chromosomal regions important for progression in clinically organ-confined prostate cancer, as the genetic changes underlying the development and progression of prostate cancer are poorly understood. MATERIALS AND METHODS: Comparative genomic hybridization (CGH) was used to search for DNA sequence copy-number changes in a series of 50 primary organ-confined prostate adenocarcinomas (pT2N0) removed by radical prostatectomy. RESULTS: CGH analysis indicated that 23 (46%) of the primary prostate adenocarcinomas showed chromosome alterations. The percentage of tumours with losses (38%) was higher than with gains (28%). Losses of 13q (24%), 8p (18%), 6q (10%), 16q (8%), 18q (6%) and 5q (6%) and gains of 17q (12%), 20q (12%), 9q (10%), 17p (8%) and 8q (6%) were the most frequent alterations. Amplifications were found at 8q24-qter. Minimal overlapping regions of loss, indicative of the presence of tumour-suppressor genes, were mapped to 13q21.1-q21.3 and 8p21.2, and minimal overlapping regions of gain, indicative of the presence of oncogenes, were found at 9q34.4-qter, 17q25-qter and 20q13.3-qter. There was a significant association between Gleason score and losses and gains (P = 0.003), and an association between chromosomal imbalance and high histological grade (P = 0.008). CONCLUSION: These results suggest that losses or gains of DNA in these regions are important for prostate cancer progression, and document the spectrum of chromosomal alterations in stage pT2N0 of clinically organ-confined prostate cancer.     

The accuracy of needle biopsy in the characterization of prostate cancer with the use of gleason and gaeta systems

Summary Histological material of prostatic carcinoma of 73 patients was reviewed for the purposes of assessing the accuracy and correlation of the initial needle biopsy with the total prostatectomy specimen. Utilizing two prevalent grading systems (Gleason and Gaeta), there was an accuracy of 90% when the two samples graded a well-differentiated carcinoma and an agreement of 70% in the assessment of moderately-differentiated lesions. The use of either system also correlated with the pathological stage of the disease in this group of patients with clinically localized prostate cancer. It is concluded that the prostate needle biopsy is highly representative of the histology of the whole tumor and it has considerable significance in the clinical evaluation of tumor volume in patients with prostate cancer.     

Loss of heterozygosity at 13q14 and 13q21 in high grade, high stage prostate cancer.

BACKGROUND: Loss of heterozygosity (LOH) at chromosome 13q has been frequently detected in prostate cancer, and three regions (i.e., 13q14, 13q21, and 13q33) may harbor tumor suppressor genes important in this neoplasm. In this study, we examined the frequency of 13q LOH in advanced prostate cancers, in order to determine the clinicopathologic relevance of 13q LOH. METHODS: LOH was determined by analyzing microsatellite markers in 41 cases of microdissected predominantly high grade prostate cancer tissues and their matched nonneoplastic cells. The results were compared with those generated previously for lower grade, asymptomatic cancers. RESULTS: The frequencies of LOH at 13q14, 13q21, and 13q33 were 62% (21/34), 57% (20/35), and 34% (11/32), respectively. In comparison to previous results, LOH at 13q14 and 13q21 but not 13q33 was more frequent in prostate cancers that produced local clinical symptoms (bladder outlet obstruction) than those that did not (P < 0.05). LOH at 13q14 was also significantly more frequent in high grade and high stage cancers than those that were lower grade and lower stage (P < 0.05). CONCLUSIONS: Although the target genes on 13q have not been identified in carcinomas of the prostate, LOH at 13q14 in particular is associated with clinically significant prostate cancers. Further fine mapping of these loci may lead to identification of tumor suppressor genes that are deleted in aggressive carcinomas of the prostate.     

Patterns of allelic loss of synchronous adenocarcinomas of the lung

Distinction of multiple primary lung carcinomas from intrapulmonary metastases using empiric clinical and histopathologic criteria can be difficult. Recent advances have provided several molecular markers that can be used for clonal analysis of separate tumor nodules and enhance tumor staging and subsequent treatment and prognosis. To address this issue, we performed a microdissection-based allelotyping of 20 cases of histologically similar, pathologic stage T4 adenocarcinomas (ADCs). Loss of heterozygosity (LOH) analysis included a panel of 15 polymorphic microsatellite markers located on 1p, 3p, 5q, 9p, 9q, 10q, 17p, and 22q. The tumor size, visceral pleural and angiolymphatic invasion, lymph node status, outcome, and survival were assessed. Allelotypes of 60 cases of solitary primary non-small cell lung carcinomas (NSCLC) (stages I-II) were used to define the percentage of discordant LOH patterns within solitary primary lung carcinoma that would discriminate between survivors and nonsurvivors. These criteria were used in the analysis of pathologic stage T4 ADC. Two groups of stage T4 cases were created: molecularly homogenous (< or = 40% discordances) (14 cases, 70%), and molecularly heterogenous (>40% discordances) (6 cases, 30%). Molecularly homogenous tumors were more frequently associated with visceral pleural invasion (92% vs. 8%) (P = 0.018). Allelotype did not correlate with age, gender, tumor size, tumor differentiation, lymph node status, angiolymphatic invasion, survival, or outcome. Our study showed that discordant and concordant genotypic profiles exist in morphologically similar synchronous ADC of the lung.     

Oncogenes and tumor suppressor genes in prostate cancer: a review

The activation of oncogenes and inactivation of tumor suppressor genes (TSGs) have been implicated in the development of many human and animal malignancies. Changes in certain specific genes have been shown to be of potential value for diagnosis and prognosis, as well as treatment, of some cancers. By contrast, no oncogene has been correlated conclusively at the DNA level with the initiation and progression of prostate cancer, although though there are alterations in expression of a number of oncogenes (i.e., ras, c-sis, c-fos, and neu) in messenger RNA and/or protein level. It is also thought that alterations of certain known TSGs, such as p53, KAII, and E-cadherin, may be important in prostate carcinogenesis; alterations of KAII (known as a metastasis suppressor gene) and p53 are more likely to be associated with the late events in the development of prostate cancers. Other TSGs, such as Rb, nm23, and PACI, require more studies to further define their role. The possible presence of TSGs in frequently altered regions on chromosomes 6q14-21, 8q, 10p, 10q, 13q, and 17p have been actively studied. Moreover, further studies on other frequently altered regions on chromosomes 2q, 5q, 15q, 16q, l7q, and 18q may provide further insight into the mechanism of prostate cancer progression. Future studies should be targeted on these putative oncogenes and TSGs and to determine whether assessment of specific gains or losses may have prognostic value in the diagnosis and treatment of prostate cancer.     

Loss of heterozygosity at 7q31.1 and 12p13-12 in advanced prostate cancer

BACKGROUND: Allelic losses on chromosome arms 2q, 3p, 5q, 6q, 7q, 8p, 9p, 10p, 10q, 11p, 11q, 12p, 13q, 16q, 17p, 17q, 18q, and 21q are reportedly associated with progression and/or initiation of prostate cancer. In the present study, we performed a polymerase chain reaction (PCR) analysis of polymorphic microsatellite loci on the human chromosomes 7 and 12p13-12 in prostate cancer tissue to investigate the extent of involvement of these regions, which may contain putative tumor suppressor genes. METHODS: Tissue samples were obtained at autopsy from 17 men who died of hormone-refractory prostate cancer at Chiba University, Japan, and affiliated hospitals between June of 1992 and June of 1995. DNA from normal tumor or metastatic tissue was used as the template for PCR amplification of a set of 16 polymorphic microsatellite loci on human chromosome 7 and 6 loci on the human chromosome region 12p13-12. RESULTS: The frequencies of cases with loss of heterozygosity (LOH) at 7q31.1 were 8% in primary tumor tissue and 11% in metastatic tissue. The frequencies of cases with LOH at 12p13-12 were 12% in primary tumor tissue and 25% in metastatic tumor tissue. CONCLUSIONS: In the present study, the frequencies of LOH at 7q31.1 were lower than in Western patients, suggesting that LOH in this region is not related to progression of prostate cancer in Japanese patients. The frequency of LOH at 12p13-12 was similar to that reported in Western countries, indicating that 12p13-12 may contain a tumor suppressor gene of prostate cancer.     

Oncogene amplification and inactivation of tumor suppressor genes in urological malignant tumors--the application of restriction fragment length polymorphism analysis]

We applied restriction fragment length polymorphism (RFLP) analysis to 24 cases of renal cell carcinomas (RCC), 18 cases of prostate adenocarcinomas (PC), and 11 cases of transitional cell carcinomas (TCC) in the renal pelvis to study the oncogene amplification and inactivation of tumor suppressor genes. All of the cases showed no amplification nor gross rearrangements of the Harvey ras, c-myc, c-fos, c-myb, EGFR and PDGFR. In contrast, RFLP analyses demonstrated allelic losses interpreted as inactivational events of TSGs among the tumor forms studied. RCC had allelic losses on the short arm of chromosome 3 (3p) (68%), the long arm of chromosome 18 (18q) (33%), Y chromosome (29%), and 17p (27%) at high frequencies. PC showed frequent allelic losses on 16q (67%), 8p (50%), 18q (43%), 10p (40%), and 10q (38%). TCC had allelic losses on 17p (73%), 11p (64%), and 9p (40%). It was likely that the cases with the more malignant grade tumor had the more allelic losses.     

Loss of heterozygosity in chromosomal region 16q24.3 associated with progression of prostate cancer

BACKGROUND: The molecular mechanisms underlying the development and progression of prostate cancer have remained poorly understood. To find out potential genetic markers likely to underlie tumor progression, the pattern of allelic loss on chromosome arm 16q in matched primary, locally recurrent, and metastatic prostate cancer specimens was analyzed in the present study. METHODS: The frequency of loss of heterozygosity (LOH) in 74 tumor specimens (62 primary cancer foci and 12 metastatic tumors) collected from 33 prostate cancer patients was determined by fragment analysis using 17 polymorphic microsatellite markers. RESULTS: The overall frequency of patients showing allelic loss at one or more loci on 16q was 68% (21/31) in primary tumors and 90% (28/31) in recurrent tumors. Of the individual markers, D16S520, locating in region 16q24.3, exhibited a statistically significant development of LOH during disease recurrence (P < 0.01). Regarding distant metastases, instead, there seemed to be no allelic loss events exclusively typical of metastatic tumors at 16q. CONCLUSIONS: The data suggest the location of gene(s) related to prostate cancer progression at 16q24.3.     

Expression of calretinin,thrombomodulin, keratin 5, and mesothelin in lung carcinomas of different types: an immunohistochemical analysis of 596 tumors in comparison with epithelioid mesotheliomas of the pleura

Several immunohistochemical markers, among them calretinin, thrombomodulin (CD141), keratin 5, and mesothelin, have been documented or suggested as useful markers for positive identification of mesothelioma and to differentiate it from pulmonary adenocarcinoma; numerous studies have documented their variable specificity. However, expression of these markers in other types of lung carcinomas has not been systematically explored, although these tumors can enter in the differential diagnosis of mesothelioma. In this study we immunohistochemically evaluated 596 lung carcinomas of different types for the four above-mentioned mesothelioma markers, all of which reacted with a great majority of epithelioid mesotheliomas studied for comparison. Calretinin expression was common in giant cell carcinomas (67%), small cell carcinomas (49%), and large cell carcinomas (38%), whereas it was rare in usual adenocarcinomas but slightly more common in those with neuroendocrine differentiation (11% and 17%, respectively). Thrombomodulin was present in all keratinizing squamous carcinomas and the great majority (87%) of nonkeratinizing tumors in a membrane-staining pattern. It was moderately common in small cell (27%) and large cell carcinomas (25%) but relatively rare in adenocarcinomas (13%). Keratin 5 was expressed in all keratinizing and the great majority (87%) of nonkeratinizing squamous carcinomas, and a majority of large cell carcinomas (56%) and some small cell carcinomas (27%). It was rare in acinar adenocarcinomas (12%) and absent in those with neuroendocrine differentiation. Mesothelin was present in more than half (53%) of adenocarcinomas and a minority (13%) of large cell carcinomas but was absent in small cell carcinomas. In squamous carcinomas it was more often seen in nonkeratinizing versus keratinizing tumors (31% vs 16%). These results show that each of these "mesothelioma" markers reacts with different subsets of pulmonary carcinomas with a variable frequency; this should be considered when using these markers in the differential diagnosis of thoracic tumors.     

Molecular genetics of prostate cancer

Despite the substantial clinical importance of prostate cancer, the molecular mechanisms underlying the development and progression of the disease are poorly understood. The aim of molecular genetics is to reveal the genetic alterations and genes that are involved in disease processes. Linkage analysis have already implicated four chromosomal loci that may harbour prostate cancer susceptibility genes. In addition, chromosomal alterations in prostate tumors have been studied using several techniques, such as comparative genomic hybridization. These analyses have indicated that losses of chromosomes 6q, 8p, 10q, 13q, and 16q, as well as gains of 7, 8q, and Xq are particularly common in prostate cancer. There is also a strong evidence, that genes, such as androgen receptor gene (AR), e-cadherin, and PTEN, are involved in the development and progression of prostate cancer. However, the target genes for most of the above mentioned chromosomal alterations as well as the genes predisposing to prostate cancer have not been cloned yet. The identification of those genes should be the utmost goal of basic research of prostate cancer, today.     

Allelic imbalance in hereditary and sporadic prostate cancer

BACKGROUND: In this study, we evaluate the pattern of allelic imbalance (AI) in both sporadic prostate cancer (SPC) and hereditary prostate cancer (HPC) at loci that frequently show allelic imbalance in sporadic prostate cancer, or are believed to have a putative role in the disease. METHODS: DNA obtained from 35 sporadic tumors and 46 hereditary tumors were tested for AI, by using a panel of 35 microsatellite markers. RESULTS: Chromosomal regions that display high frequencies of AI (>or=30%) in HPC include 1q, 5q, 7q, 8p, 13q, 16q, 17q, 18q, and 20q. In SPC, high frequencies of AI were found at 5q, 7q, 8p, 10q, 13q. Main differences (delta >or= 20%) in AI between HPC and SPC were at 1q, 10q, 17q, 18q, and 20q. CONCLUSION: AI at the prostate cancer susceptibility loci HPC1, PCaP, and HPC20 was seen more often in HPC compared with SPC. It appears that there are marked differences in the pattern of AI between sporadic and hereditary PCa.     

Clinical and molecular features of treatment‐related neuroendocrine prostate cancer

Treatment‐related neuroendocrine prostate cancer is a lethal form of prostate cancer that emerges in the later stages of castration‐resistant prostate cancer treatment. Treatment‐related neuroendocrine prostate cancer transdifferentiates from adenocarcinoma as an adaptive response to androgen receptor pathway inhibition. The incidence of treatment‐related neuroendocrine prostate cancer has been rising due to the increasing use of potent androgen receptor pathway inhibitors. Typically, treatment‐related neuroendocrine prostate cancer is characterized by either low or absent androgen receptor expression, small cell carcinoma morphology and expression of neuroendocrine markers. Clinically, it manifests with predominantly visceral or lytic bone metastases, bulky tumor masses, low prostate‐specific antigen levels or a short response duration to androgen deprivation therapy. Furthermore, although the tumor initially responds to platinum‐based chemotherapy, the duration of the response is short. Based on the poor prognosis, it is imperative to identify novel molecular targets for treatment‐related neuroendocrine prostate cancer. Recent advances in genomic and molecular research, supported by novel in vivo models, have identified some of the key molecular characteristics of treatment‐related neuroendocrine prostate cancer. The gain of MYCN and AURKA oncogenes, along with the loss of tumor suppressor genes TP53 and RB1 are key genomic alterations associated with treatment‐related neuroendocrine prostate cancer. Androgen receptor repressed genes, such as BRN2 and PEG10, are also necessary for treatment‐related neuroendocrine prostate cancer. These genetic changes converge on pathways upregulating genes, such as SOX2 and EZH2, that facilitate lineage plasticity and neuroendocrine differentiation. As a result, on potent androgen receptor pathway inhibition, castration‐resistant prostate cancer transdifferentiates to treatment‐related neuroendocrine prostate cancer in a clonally divergent manner. Further understanding of the disease biology is required to develop novel drugs and biomarkers that would help treat this aggressive prostate cancer variant.