Pun Ching Philip Ip

PET/Computed Tomography Transformation of Oncology

Over the last quarter of a century, fluorine-18-fluorodeoxyglucose (FDG) PET/computed tomography (CT) has revolutionized the diagnostic algorithm of ovarian cancer, impacting on the initial disease evaluation including staging and surgical planning, treatment response assessment and prognostication, to the most important role in detection of recurrent disease. The role of FDG PET/CT is expanding with the adoption of new therapeutic agents. Other non-FDG tracers have been explored with fibroblast activation protein inhibitor being promising. Novel tracers may provide the basis for future theragnostic work. This article will review the evolution and impact of PET/CT in ovarian cancer management.

Clinical Behavior and Molecular Landscape of Stage I p53-Abnormal Low-Grade Endometrioid Endometrial Carcinomas

Abstract Purpose: The clinical significance of the p53-abnormal (p53abn) molecular subtype in stage I low-grade endometrioid endometrial carcinoma (EEC) is debated. We aimed to review pathologic and molecular characteristics, and outcomes of stage I low-grade p53abn EEC in a large international cohort. Experimental Design: Previously diagnosed stage I p53abn EC (POLE–wild-type, mismatch repair–proficient) low-grade EEC from Canadian retrospective cohorts and PORTEC-1&2 trials were included. Pathology review was performed by six expert gynecologic pathologists blinded to p53 status. IHC profiling, next-generation sequencing, and shallow whole-genome sequencing was performed. Kaplan–Meier method was used for survival analysis. Results: We identified 55 stage I p53abn low-grade EEC among 3,387 cases (2.5%). On pathology review, 17 cases (31%) were not diagnosed as low-grade EEC by any pathologists, whereas 26 cases (47%) were diagnosed as low-grade EEC by at least three pathologists. The IHC and molecular profile of the latter cases were consistent with low-grade EEC morphology (ER/PR positivity, patchy p16 expression, PIK3CA and PTEN mutations) but they also showed features of p53abn EC (TP53 mutations, many copy-number alterations). These cases had a clinically relevant risk of disease recurrence (5-year recurrence-free survival 77%), with pelvic and/or distant recurrences observed in 12% of the patients. Conclusions: A subset of p53abn EC is morphologically low-grade EEC and exhibit genomic instability. Even for stage I disease, p53abn low-grade EEC are at substantial risk of disease recurrence. These findings highlight the clinical relevance of universal p53-testing, even in low-grade EEC, to identify women at increased risk of recurrence.

Single-cell EMT-related transcriptional analysis revealed intra-cluster heterogeneity of tumor cell clusters in epithelial ovarian cancer ascites

Malignant ascites of epithelial ovarian cancer is a metastatic tumor microenvironment in which large amounts of disseminated single cells (DSCs) and disseminated tumor cell clusters (DTCCs) are commonly observed. The tumor cell clusters are known to be more aggressive than individual tumor cells in cancer metastasis; however, little is known about the mechanism. Applying single-cell epithelial-to-mesenchymal transition (EMT)-related transcriptional analysis in 120 DSCs and 195 intra-cluster cells from 27 DTCCs, we demonstrated that DTCCs were heterogeneous cellular units comprised of epithelial tumor cells, leukocytes, and cancer-associated fibroblasts (CAFs). Through the analysis of intra-DTCC heterogeneity, we identified that CAFs induced EMT of tumor cells via TGFβ signaling within the DTCC microenvironment. The activation of EMT program, in particular the upregulation of ZEB2, enabled the acquisition of additional chemoresistance and metastasis abilities of the intra-DTCC tumor cells, which resulted in the aggressiveness of DTCCs.

Digital image analysis of gland-to-stroma ratio by CD10 objectively differentiates between low-grade endometrioid carcinoma and atypical hyperplasia on endometrial biopsy

Distinguishing between endometrial atypical hyperplasia/endometrial intraepithelial neoplasia (EAH/EIN) and grade 1 endometrial endometrioid carcinoma (EEC) requires the evaluation of gland-to-stromal ratio, presence of stromal invasion, extent of epithelial proliferation and nuclear alterations. In small biopsies, stromal invasion may not always be sampled, so other features become more important. However, assessing of some of these features may be subjective. Digital analysis improves diagnostic uniformity, and when combined with CD10 immunostain, it can potentially become a useful objective parameter. Endometrial biopsies with a diagnosis of EAH/EIN or EEC matched were retrieved with subsequent hysterectomy for reference diagnosis. CD10 immunohistochemistry was applied to the biopsies, followed by scanning and annotation. Pixel-accurate stromal percentages were deduced from digitised whole-slide images from a test cohort. An optimal stromal percentage cut-off, thus gland-to-stroma ratio, was extrapolated from the receiver operating characteristic curve. A separate cohort was used to validate the diagnostic performance of the determined gland-to-stroma cut-off. Seventy endometrial biopsies were included in the test cohort, comprising 48 grade 1 EECs and 22 EAH/EINs. The mean stromal percentage was 15.69% for EEC and 33.65% for EAH/EIN (all endometrial tissue annotated/analysed) and 14.77% for EEC and 31.88% for EAH/EIN (only lesional tissue annotated/analysed). The corresponding gland-to-stroma ratio was 5:1 for EEC and 2:1 for EAH/EIN. The areas under curve were 0.758 (p=0.001) (all endometrial tissue) and 0.761 (p=0.001) (only lesional tissue), (p=0.001). In the validation cohort, a cut-off of 30% CD10-stained stroma (7:3 gland-to-stroma ratio) was superior in diagnostic performance than the H&E diagnosis (p=0.042). Evaluation of gland-to-stroma ratio using CD10 immunostain and digital image analysis is a robust and objective method for distinguishing between grade 1 EEC and EAH/EIN in small biopsies. A cut-off >7:3 is highly indicative of EEC.

Inhibition of Aberrantly Overexpressed Polo-like Kinase 4 Is a Potential Effective Treatment for DNA Damage Repair–Deficient Uterine Leiomyosarcoma

Abstract Purpose: Uterine leiomyosarcoma (LMS) is an aggressive sarcoma and a subset of which exhibits DNA repair defects. Polo-like kinase 4 (PLK4) precisely modulates mitosis, and its inhibition causes chromosome missegregation and increased DNA damage. We hypothesize that PLK4 inhibition is an effective LMS treatment. Experimental Design: Genomic profiling of clinical uterine LMS samples was performed, and homologous recombination (HR) deficiency scores were calculated. A PLK4 inhibitor (CFI-400945) with and without an ataxia telangiectasia mutated (ATM) inhibitor (AZD0156) was tested in vitro on gynecologic sarcoma cell lines SK-UT-1, SKN, and SK-LMS-1. Findings were validated in vivo using the SK-UT-1 xenograft model in the Balb/c nude mouse model. The effects of CFI-400945 were also evaluated in a BRCA2-knockout SK-UT-1 cell line. The mechanisms of DNA repair were analyzed using a DNA damage reporter assay. Results: Uterine LMS had a high HR deficiency score, overexpressed PLK4 mRNA, and displayed mutations in genes responsible for DNA repair. CFI-400945 demonstrated effective antitumor activity in vitro and in vivo. The addition of AZD0156 resulted in drug synergism, largely due to a preference for nonhomologous end-joining DNA repair. Compared with wild-type cells, BRCA2 knockouts were more sensitive to PLK4 inhibition when both HR and nonhomologous end-joining repairs were impaired. Conclusions: Uterine LMS with DNA repair defects is sensitive to PLK4 inhibition because of the effects of chromosome missegregation and increased DNA damage. Loss-of-function BRCA2 alterations or pharmacologic inhibition of ATM enhanced the efficacy of the PLK4 inhibitor. Genomic profiling of an advanced-stage or recurrent uterine LMS may guide therapy.

Endometrial Carcinomas With a Somatically Derived Yolk Sac Tumor Component Share Molecular Similarities to p53–abnormal Endometrial Carcinomas and Germ Cell Tumors

Primary endometrial carcinomas with somatically derived yolk sac tumor (YST) components are rare. We analyzed 23 such cases using detailed clinicopathologic, immunohistochemical, and molecular methods. The median patient age was 68 years. Elevated serum alpha-fetoprotein (AFP) was detected in 76.9% (10/13) of tested cases. International Federation of Gynecology and Obstetrics (FIGO) 2009 stages were I (n = 12, 55%), II (n = 1, 5%), III (n = 5, 23%), IV (n = 4, 18%), and unknown in one. Histologic YST patterns included glandular (87%), papillary (52%), solid (48%), endodermal sinus (17%), hepatoid (17%), and reticular (13%) architectures. The associated Müllerian-type neoplasms were endometrioid carcinoma (n = 17), carcinosarcoma (n = 3), serous carcinoma (n = 2), and clear cell carcinoma (n = 1). Immunohistochemically, 17 cases (74%) exhibited mutation-type p53 staining, and 2 (9%) were mismatch repair-deficient (MMRd). YST components uniformly expressed glypican-3 and spalt-like transcription factor 4 (SALL4), whereas 17 (74%) also expressed AFP. HER2 positivity was seen in 13 of 21 tested (62%; four 3+, three 2+, and six 1+). Molecular analysis revealed TP53 variants in 16 of 22 cases (73%) without POLE hotspot mutations. According to The Cancer Genome Atlas molecular classification, 17 tumors were p53-abnormal (74%), 2 (9%) MMRd, 4 (17%) were no specific molecular profile, and none was POLE-ultramutated. Recurrent copy number gains involved CCNE1 (9/22, 41%), 1q44 (12/14, 86%), and 3q26.32 (8/14, 57%). Features reminiscent of germ cell tumors included amplifications at 7p21.2 (8/14, 57%) and 9p21.3 (11/14, 79%), polysomy or amplification of chromosome 12p (6/22, 27%), deletion at 11q24.3 (8/14, 57%), and a high frequency of T>C nucleotide substitutions. Follow-up showed 15 patients (75%) had died of disease or were alive with disease; 12 of these 15 cases were p53-abnormal. Overall survival was significantly poorer than in other molecular subtypes of endometrial carcinoma. These tumors should therefore be regarded as high grade (grade 3) by definition. In summary, endometrial carcinomas with a somatically derived YST component are highly aggressive, predominantly p53-abnormal, with smaller subsets classified as MMRd or no specific molecular profile. Recognition of the YST component is crucial, and biomarker profiling may reveal therapeutic targets.