Stage IV lung carcinoids: spectrum and evolution of proliferation rate, focusing on variants with elevated proliferation indices.

The spectrum and evolution of proliferation rates in stage IV lung carcinoids is poorly defined. In particular, there are limited data on the prevalence and characteristics of tumors exceeding the standard upper proliferative criteria-as defined largely based on early-stage carcinoids-in metastatic setting. Sixty-six patients with stage IV lung carcinoids were identified, and all evaluable samples (n = 132; mean 2 samples per patient) were analyzed for mitotic counts and Ki-67 rate. Clinicopathologic and genomic features associated with elevated proliferation rates (>10 mitoses per 2 mm2 and/or >20% hot-spot Ki-67), and evolution of proliferation rates in serial specimens were analyzed. We found that mitoses and/or Ki-67 exceeded the standard criteria in 35 of 132 (27%) samples, primarily (31/35 cases) at  metastatic sites. Although neuroendocrine neoplasms with >10 mitoses per 2 mm2 are currently regarded as de facto neuroendocrine carcinomas, the notion that these cases are part of the spectrum of carcinoids was supported by (1) well-differentiated morphology, (2) conventional proliferation rates in other samples from same patient, (3) genetic characteristics, including the lack of RB1/TP53 alterations in all tested samples (n = 19), and (4) median overall survival of 2.7 years, compared to <1 year survival of stage IV neuroendocrine carcinomas in the historic cohorts. In patients with matched primary/metastatic specimens (48 pairs), escalation of mitoses or Ki-67 by ≥10 points was observed in 35% of metastatic samples; clonal relationship in one pair with marked proliferative progression was confirmed by next-generation sequencing. Notably, escalation of proliferation rate was documented in a subset of metastases arising from resected typical carcinoids, emphasizing that the diagnosis of typical carcinoid in primary tumor does not assure low proliferation rate at metastatic sites. In conclusion, stage IV lung carcinoids frequently exceed the standard proliferative criteria established for primary tumors, and commonly exhibit proliferative escalation at metastatic sites. Despite the overlap of proliferation rates, these tumors show fundamental morphologic, genomic and clinical differences from neuroendocrine carcinomas, and should be classified separately from those tumors. Awareness of the increased proliferative spectrum in metastatic carcinoids is critical for their accurate diagnosis. Further studies are warranted to explore the impact of proliferation indices on prognosis and therapeutic responses of patients with metastatic carcinoids.

Rationale and Design of the Phase 3 KEYLYNK-013 Study of Pembrolizumab With Concurrent Chemoradiotherapy Followed by Pembrolizumab With or Without Olaparib for Limited-Stage Small-Cell Lung Cancer.

BACKGROUND: The current standard of care for patients with newly diagnosed limited-stage small-cell lung cancer (SCLC) is concurrent chemoradiotherapy (CCRT). The prognosis remains poor due to the aggressiveness and high risk of progression or relapse of SCLC even if an initial response is achieved. Therefore, there is an urgent unmet clinical need in this population. The multicenter, phase 3, randomized, placebo-controlled, double-blind KEYLYNK-013 study evaluates the addition of pembrolizumab to CCRT followed by pembrolizumab with or without olaparib in participants with previously untreated limited-stage SCLC. (ClinicalTrials.gov: NCT04624204). METHODS: Eligible participants aged ≥18 years with newly diagnosed, pathologically confirmed, limited-stage (ie, stage I-III) SCLC will be randomized 1:1:1 to CCRT (ie, etoposide plus carboplatin or cisplatin for 4 cycles and standard thoracic radiotherapy) plus pembrolizumab (Groups A and B) or CCRT plus placebo (Group C). In the absence of disease progression, participants will receive pembrolizumab plus placebo (Group A), pembrolizumab plus olaparib (Group B), or placebo (Group C). Dual primary endpoints are progression-free survival per RECIST version 1.1 by blinded independent central review and overall survival. RESULTS: Enrollment began in December 2020 and is ongoing at approximately 150 sites. CONCLUSIONS: KEYLYNK-013 will provide valuable information on the efficacy and safety of pembrolizumab plus CCRT and pembrolizumab with or without olaparib post CCRT in participants with limited-stage SCLC.

Expression of GATA3 in MDA-MB-231 triple-negative breast cancer cells induces a growth inhibitory response to TGFß.

Transforming growth factor (ß1TGFß1) can promote proliferation in late stage cancers but acts as a tumor suppressor in normal epithelial cells and in early stage cancers. Although, the TGFß pathway has been shown to play a key role in tumorigenesis and metastasis, only a limited number of models have been developed to understand this process. Here, we present a novel model system to discern this paradoxical role of TGFß1 using the MDA-MB-231 (MB-231) cell line. The MB-231 triple-negative breast cancer cell line has been extensively characterized and has been shown to continue to proliferate and undergo epithelial-to-mesenchymal transition (EMT) upon TGFß1 stimulation. We have previously shown by microarray analysis that expression of GATA3 in MB-231 cells results in reprogramming of these cells from a basal to a luminal subtype associated with a reduction of metastasis and tumorigenesis when implanted as xenografts. We now demonstrate that GATA3 overexpression in these cells results in a reduction of TGFß1 response, reversal of EMT, and most importantly, restoration of sensitivity to the inhibitory effects on proliferation of TGFß1. Microarray analysis revealed that TGFß1 treatment resulted in reduction of several cell cycle effectors in 231-GATA3 cells but not in control cells. Furthermore, our microarray analysis revealed a significant increase of BMP5 in 231-GATA3 cells. We demonstrate that combined treatment of MB-231 control cells with TGFß1 and BMP5 results in a significant reduction of cellular proliferation. Thus, this model offers a means to further investigate potentially novel mechanisms involved in the switch in response to TGFß1 from tumor promoter to tumor suppressor through the reprogramming of a triple-negative breast cancer cell line by the GATA3 transcription factor.

BRCA mutation status and determinant of outcome in women with recurrent epithelial ovarian cancer treated with pegylated liposomal doxorubicin.

Epithelial ovarian cancer (EOC) patients with BRCA mutations (BRCA +) benefit from platinum-based treatment more than noncarriers. Impaired ability to repair DNA by homologous recombination increases their chemosensitivity. We investigated whether BRCA + predicts for improved outcome following pegylated liposomal doxorubicin (PLD) for recurrence. Recurrent EOC patients receiving second- or third-line PLD from 1998 to 2009 in 4 institutions (Tel Aviv, New York, Padua, and Jerusalem) were subjected to retrospective comparisons between 40 (25.8%) patients who were BRCA +, and 115 (74.2%) deemed nonhereditary (NH). Median age was 59 years (range 31-83); 111 (72%) had a platinum-free interval more than 6 months [PLD alone (n = 65) and PLD plus platinum (n = 90)]; 104 received PLD in second-line and 51 in third-line. BRCA + versus NH comparisons: median time to treatment failure (TTF) 15.8 months [95% confidence interval (CI): 11.4-21.6] versus 8.1 months (95% CI: 6.1-10.3; P = 0.009); overall survival (OS) 56.8 months (95% CI: 32.5-indeterminate) versus 22.6 months (95% CI: 17.0-34.1; P = 0.002). In multivariate Cox models BRCA status was significantly associated with TTF (HR = 1.66; 95% CI: 1.08-2.55; P = 0.02) and OS (adjusted HR 2.07; 95% CI: 1.18-3.60; P = 0.01). Adjusted HR relating platinum sensitivity to OS was 1.58 (95% CI: 0.93-2.68; P = 0.09); no significant association found with age at diagnosis, line of PLD or combinations, or institution. In this retrospective analysis, recurrent EOC BRCA mutation carriers treated with PLD had an improved outcome, and this result seemed to be independent of platinum sensitivity. Tumors arising in a background of defective BRCA function are more sensitive than other EOCs to DNA-damaging agents such as PLD, even after acquiring platinum resistance.

Potential sites of bioactive gibberellin production during reproductive growth in Arabidopsis.

Gibberellin 3-oxidase (GA3ox) catalyzes the final step in the synthesis of bioactive gibberellins (GAs). We examined the expression patterns of all four GA3ox genes in Arabidopsis thaliana by promoter-beta-glucuronidase gene fusions and by quantitative RT-PCR and defined their physiological roles by characterizing single, double, and triple mutants. In developing flowers, GA3ox genes are only expressed in stamen filaments, anthers, and flower receptacles. Mutant plants that lack both GA3ox1 and GA3ox3 functions displayed stamen and petal defects, indicating that these two genes are important for GA production in the flower. Our data suggest that de novo synthesis of active GAs is necessary for stamen development in early flowers and that bioactive GAs made in the stamens and/or flower receptacles are transported to petals to promote their growth. In developing siliques, GA3ox1 is mainly expressed in the replums, funiculi, and the silique receptacles, whereas the other GA3ox genes are only expressed in developing seeds. Active GAs appear to be transported from the seed endosperm to the surrounding maternal tissues where they promote growth. The immediate upregulation of GA3ox1 and GA3ox4 after anthesis suggests that pollination and/or fertilization is a prerequisite for de novo GA biosynthesis in fruit, which in turn promotes initial elongation of the silique.