Gastric Metastasis of Prostate Cancer as an Unusual Presentation Using 68Ga-Prostate-Specific Membrane Antigen PET/CT

Mitochondria in tumour progression: a network of mtDNA variants in different types of cancer

Background

Mitochondrial participation in tumorigenesis and metastasis has been studied for many years, but several aspects of this mechanism remain unclear, such as the association of mitochondrial DNA (mtDNA) with different cancers. Here, based on two independent datasets, we modelled an mtDNA mutation-cancer network by systematic integrative analysis including 37 cancer types to identify the mitochondrial variants found in common among them.

Results

Our network showed mtDNA associations between gastric cancer and other cancer types, particularly kidney, liver, and prostate cancers, which is suggestive of a potential role of such variants in the metastatic processes among these cancer types. A graph-based interactive web tool was made available at www2.lghm.ufpa.br/mtdna. We also highlighted that most shared variants were in the MT-ND4, MT-ND5 and D-loop, and that some of these variants were nonsynonymous, indicating a special importance of these variants and regions regarding cancer progression, involving genomic and epigenomic alterations.

Conclusions

This study reinforces the importance of studying mtDNA in cancer and offers new perspectives on the potential involvement of different mitochondrial variants in cancer development and metastasis.

68Ga PSMA Uptake at Roux-en-Y Eso-jejunostomy Junction Mimicking the Recurrence of Gastric Carcinoma in PET/CT

A 67-year-old male patient had undergone total gastrectomy and Roux-en-Y eso-jejunostomy 3 years ago for the treatment of tubular adenocarcinoma located at the corpus of the stomach. The patient was diagnosed with Gleason score 8 (4+4) metastatic prostate cancer during the follow-up period and received hormone therapy. Owing to his elevated prostate-specific antigen levels (77 ng/mL), his clinician referred him gallium-68 (⁶⁸Ga) prostate-specific membrane antigen 11 (PSMA) positron emission tomography/computed tomography (PET/CT) for restaging. PET/CT showed multiple ⁶⁸Ga PSMA receptor-positive skeletal lesions and linear PSMA activity at the eso-jejunostomy junction. He was then referred to undergo ¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) PET/CT to screen for gastric carcinoma recurrence. PET/CT images demonstrated no ¹⁸F-FDG avid lesion. However, endoscopy and biopsy performed with samples from the eso-jejunostomy junction revealed superficial benign squamous epithelial fragments.

Diffuse Pulmonary Metastases From Prostate Cancer on 68Ga PSMA PET/CT

A 63-year-old man, recently diagnosed with carcinoma of the prostate (Gleason's score 4+4), with serum prostate-specific antigen 189.2 ng/mL, underwent Ga PSMA PET/CT scan for pretreatment staging. The study revealed abnormal tracer uptake in the prostatic bed region, the pelvic, abdominal, and mediastinal lymph nodes and diffuse metastases to the bilateral lungs. The lung metastasis was proved to be metastatic adenocarcinoma from analysis of bronchoalveolar lavage.