Abstract
Differentiating small cell neuroendocrine carcinoma (SCNC) of the prostate from prostatic cancer with diffuse neuroendocrine (NE) differentiation based on morphological features alone can be challenging. Given that treatment strategies vary depending on histological type, accurate diagnosis is critical. This study firstly aimed to identify the accurate diagnostic factors for primary prostate NE tumors. Furthermore, the possibility of novel treatment strategies through genetic analysis is also an aim. Specifically, prostate biopsies conducted in our hospital between January 2017 and May 2020 were included. As a result seven cases of SCNC and four cases of prostatic cancer with diffuse NE differentiation were identified. No significant differences in serum neuron-specific enolase (NSE), pro-gastrin-releasing peptide (ProGRP), and prostate-specific antigen (PSA) levels were observed between SCNC and adenocarcinoma with diffuse NE differentiation. The Ki-67 labeling index was significantly higher and PSA immunoreactivity tended to be lower in SCNC. Genetic analysis did not detect any ALK mutations but confirmed several other mutations, including those of PIK3CA and TP53. In conclusion, given the heterogeneity in serum NE markers in SCNC, diagnosis based on these markers alone is difficult. A high Ki-67 labeling index and low PSA immunoreactivity may be useful for diagnosing, but p53 immunoreactivity is insufficient to distinguish these tumors. Although further studies are required to interpret the results of the genetic analysis involving ALK, PIK3CA, and TP53 mutations, the results of our genetic analysis suggest that PIK3CA mutations in SCNC of the prostate may provide a novel therapeutic strategy.
Clinicopathological and Genetic Analyses of Small Cell Neuroendocrine Carcinoma of the Prostate: Histological Features for Accurate Diagnosis and Toward Future Novel Therapies
