Novel histological prognostic factors in gastric cancer

Abstract Gastric cancer is among the most common cancer types in the world and the third most common cause of death by cancer. The prognosis of individual patients treated with surgery varies greatly. New prognostic factors are needed to complement the prognostic information provided by the currently used tumor-node-metastasis (TNM) staging system. Several novel prognostic factors that can be assessed from routinely stained hematoxylin-eosin (HE) slides have been discovered in different cancer types. They include tumor-stroma ratio (TSR), tumor budding, stromal maturity and Klintrup-Mäkinen (KM) grade. TSR is based on estimating the amount of intratumoral stroma. Tumor budding is assessed by counting tumor buds, which are single tumor cells or clusters of up to four cells detached from the main tumor mass. Assessment of stromal maturity is based on presence of thick eosinophilic collagen bundles in the immature stroma. KM-grade is a method of semiquantitatively classifying the lymphocytic infiltrate present at the border of the tumor. All these factors have prognostic value in different cancer types, but their relevance in gastric cancer is unknown. In this thesis, prognostic value of TSR, tumor budding, stromal maturity and KM-grade in gastric cancer was studied, mainly in a large patient cohort from Oulu University Hospital. TSR, tumor budding, stromal maturity and KM-grade were all independent prognostic factors in the patient cohort. TSR and tumor budding were assessed with high interobserver agreement, while stromal maturity and KM-grade were assessed with moderate interobserver agreement. Based on our results, TSR, tumor budding, stromal maturity and KM-grade have prognostic value in gastric cancer. They could potentially be used to improve accuracy of estimating patients’ prognosis after surgery for gastric cancer.Tiivistelmä Mahasyöpä on yksi maailman yleisimmistä syöpätyypeistä ja maailman kolmanneksi yleisin syöpäkuoleman aiheuttaja. Kirurgisesti hoidettujen potilaiden ennuste vaihtelee suuresti. Uudet ennustetekijät olisivat hyödyllisiä nykyään käytetyn tumor-node-metastasis (TNM) -luokituksen antaman ennustetiedon täydentämiseksi. Useita uusia rutiinisti tehtävistä hematoksyliini-eosiini (HE) -värjätyistä laseista analysoitavissa olevia ennustetekijöitä on löydetty monista eri syöpätyypeistä. Niihin lukeutuvat kasvain-stroomasuhde (tumor-stroma ratio (TSR)), kasvaimen silmikointi, strooman kypsyys ja Klintrup-Mäkinen (KM) -aste. TSR perustuu tuumorin sisäisen strooman määrän arvioimiseen. Kasvaimen silmikointi analysoidaan laskemalla tuumorisilmujen määrä. Tuumorisilmut ovat yksittäisiä kasvainsoluja tai korkeintaan neljän solun ryhmiä, jotka ovat irronneet kasvaimen pääosasta. Strooman kypsyyden arviointi perustuu paksujen eosinofiilisten kollageenikimppujen esiintymiseen epäkypsässä stroomassa. KM-aste on semikvantitatiivinen menetelmä kasvaimen reunalla olevan lymfosyytti-infiltraatin luokitteluun. Kaikilla näistä tekijöistä on aiemmin osoitettu olevan ennustearvoa eri syöpätyypeissä, mutta niiden merkitys mahasyövässä tunnetaan puutteellisesti. Tässä väitöskirjassa tutkittiin TSR:n, kasvaimen silmikoinnin, strooman kypsyyden ja KM-asteen ennustearvoa, pääasiassa suuressa Oulun yliopistollisen sairaalan potilaskohortissa. TSR, kasvaimen silmikointi, strooman kypsyys ja KM-aste olivat kaikki itsenäisiä ennustetekijöitä. TSR:n ja kasvaimen silmikoinnin arvioinnin toistettavuus oli hyvä, ja strooman kypsyyden ja KM-asteen kohtalainen. Tuloksiemme perusteella TSR:llä, kasvaimen silmikoinnilla, strooman kypsyydellä ja KM-asteella on ennustearvoa mahasyövässä. Niitä voitaisiin mahdollisesti tulevaisuudessa hyödyntää leikattujen mahasyöpäpotilaiden ennustearvioiden parantamisessa

Tumour-stroma ratio and 5-year mortality in gastric adenocarcinoma:a systematic review and meta-analysis

Abstract Tumour-stroma ratio (TSR) is a novel potential prognostic factor in cancers and based on the proportions of stroma and tumour area. The prognostic value of TSR in gastric cancer is incompletely known. The aim of this study was to estimate prognostic significance of TSR in gastric adenocarcinoma. A search of PubMed (MEDLINE), Web of Science, EMBASE, Cochrane and Scopus databases was performed. A meta-analysis was conducted on five-year survival in gastric cancer patients using inverse variance random-effects methods. The literature search yielded 5329 potential titles, of which a total of seven studies were eligible. Results of six studies including a total of 1779 patients were pooled in the meta-analysis. Only 23 (1.3%) of the patients received neoadjuvant therapy. All six studies had a cut-off of 50% for the proportion of stroma when dividing the patients into low- and high stroma groups. Low TSR (high amount of stroma) was strongly associated with increased five-year mortality (hazard ratio 2.19, 95% CI 1.69–2.85). In conclusion, TSR is a strong prognostic factor in gastric cancer. It could be used to estimate prognosis of gastric cancer patients not receiving neoadjuvant chemotherapy. Further studies including patients receiving neoadjuvant therapy are recommended

Monocarboxylate transporters 1 and 4 and MTCO1 in gastric cancer

Abstract Background: Monocarboxylate transporters (MCTs) appear to play an important role in tumor development and aggressiveness. The present study aimed to evaluate associations between cytoplasmic MCT1, MCT4, and mitochondrial cytochrome c oxidase (MTCO1) expression and clinicopathological variables or survival in gastric cancer. Material and methods: A total of 568 gastric adenocarcinoma patients were included in this retrospective cohort study. Protein expressions were detected by immunohistochemical staining. The patients were divided into low expression and high expression groups by median value. The Chi-squared test was used to compare categorical variables. The T-test was used to compare continuous variables. Expressions were analyzed in relation to 5-year survival and overall survival. Cox regression provided HRs and 95% CIs, adjusted for confounders. Results: High cytoplasmic MCT1 expression was associated statistically significantly with higher T-class (p = 0.020). High cytoplasmic MCT4 expression was associated statistically significantly with positive lymph node status (p = 0.005) and was more common in Lauren’s intestinal type (p < 0.001). Low cytoplasmic MTCO1 expression was associated statistically significantly with positive distant metastases (p = 0.030), and high cytoplasmic MTCO1 expression was associated more often with intestinal type (p = 0.044). However, MCT1, MCT4, and MTCO1 were not associated with survival. Conclusions: Monocarboxylate receptors seem to be associated with gastric cancer progression but have no independent prognostic relevance

Tumour budding and tumour–stroma ratio in hepatocellular carcinoma

Abstract Background: Tumour budding and low tumour–stroma ratio (TSR) are associated with poor prognosis in some cancers, but their value in Western hepatocellular carcinoma is unclear. The prognostic value of tumour budding and TSR in hepatocellular carcinoma was examined. Methods: Some 259 hepatocellular carcinoma patients treated in Oulu University Hospital 1983–2018 were included in this retrospective cohort study. Tumour budding and TSR were analysed from the haematoxylin- and eosin-stained original diagnostic slides, by dividing patients into bud-negative (0 bud) or bud-positive (≥1 bud) groups, and into high TSR (<50%) and low TSR (≥50%) groups. Surgically treated patients (n = 47) and other treatments (n = 212) were analysed separately. Primary outcomes were overall, and disease-specific 5-year mortality was adjusted for confounding factors. Results: Surgically treated patients with positive tumour budding had increased 5-year overall (adjusted HR 3.87, 95% CI 1.10–13.61) and disease-specific (adjusted HR 6.17, 95% CI 1.19–31.90) mortality compared with bud-negative patients. In surgically treated patients, TSR had no effect on 5-year overall (adjusted HR 2.03, 95% CI 0.57–7.21) or disease-specific (adjusted HR 3.23, 95% CI 0.78–13.37) mortality. No difference in survival related to tumour budding and TSR in non-surgically treated patients was observed. Conclusions: Tumour budding is a prognostic factor in surgically treated hepatocellular carcinoma

Toll-like receptors 3, 7, 8, and 9 in gastric cancer

Abstract Toll-like receptors (TLRs) have been shown to have anti-tumor, pro-tumor, or even dual effects in cancer, and are thus potential prognostic biomarkers and immunotherapeutic targets. The present study aimed to evaluate associations between endosomal TLRs, namely TLR3, TLR7, TLR8, and TLR9, expression and clinicopathological variables and survival in gastric cancer. A total of 564 gastric adenocarcinoma patients were included in this retrospective cohort study. Samples and clinicopathological data were retrieved and organized into tissue microarray blocks. Protein expressions were detected by immunohistochemical staining. The patients were divided into low expression and high expression groups by median values of expression. Cox regression provided hazard ratios (HR) with 95% confidence intervals (CI), adjusted for confounders. Patients with high nuclear TLR3 expression had significantly poorer 5-year survival than the low nuclear TLR3 expression group in the univariable analysis (crude HR 1.31, 95% CI 1.07–1.60). With radically resected patients, poor prognosis was also seen in the multivariable analysis (adjusted HR 1.38, 95% CI 1.08–1.77). Cytoplasmic TLR3, TLR7, TLR8, and TLR9 were not associated with 5-year survival. In conclusion, high nuclear TLR3 expression seems to have prognostic impact in gastric cancer, while TLR7, TLR8, and TLR9 do not

Tumor budding and prognosis in gastric adenocarcinoma

Abstract Tumor budding has been associated with poor prognosis in several cancer types, but its significance in gastric cancer is unknown. The aim of this study was to assess the prognostic significance of tumor budding in gastric adenocarcinoma, and its main histologic types. Some 583 gastric adenocarcinoma patients who underwent surgery in Oulu University Hospital during the years 1983–2016 were included in this retrospective cohort study. Tumor budding was counted per 0.785 mm² fields from the slides originally used for diagnostic purposes. Patients were divided into low-budding (<10 buds) and high-budding (≥10 buds) groups. Tumor budding was analyzed in relation to 5-year survival and overall survival. Cox regression was used to calculate hazard ratios (HR) with 95% confidence intervals (CI), adjusted for confounders. Determining tumor budding was difficult in diffuse-type cancer due to the uncohesive growth pattern of these tumors. Patients with high tumor budding had worse 5-year survival compared with patients with low tumor budding (adjusted HR, 1.55; 95% CI, 1.20–2.01). In intestinal-type adenocarcinomas, the high-budding group had significantly poorer 5-year survival compared with the low-budding group (adjusted HR, 1.57; 95% CI, 1.14–2.15). There were no differences in 5-year survival between the budding groups in the diffuse type adenocarcinoma. In conclusion, high tumor budding is an independent prognostic factor in gastric adenocarcinoma, but its value is limited to the intestinal type of gastric adenocarcinoma. In diffuse type gastric adenocarcinoma, the assessment of tumor budding is hardly feasible, and it does not have prognostic relevance

Histological assessment of stromal maturity as a prognostic factor in surgically treated gastric adenocarcinoma

Abstract Aims: Histological assessment of stromal maturity is a potential prognostic factor in colorectal cancer, but its applicability in gastric adenocarcinoma is completely unknown. The aim of this study was to evaluate the feasibility and prognostic significance of assessing stromal maturity in gastric adenocarcinoma. Methods and results: This study was conducted retrospectively in a cohort of 583 gastric adenocarcinoma patients treated surgically in Oulu University Hospital, Finland between 1983 and 2016. The original diagnostic slides were used for assessment of stromal maturity. Patients were divided into mature stroma and immature stroma groups, and stromal maturity was analysed in relation to 5‐year and overall survival (OS). The primary outcome of the study was 5‐year survival, and the secondary outcome was OS. The kappa‐coefficient for interobserver agreement was 0.609. Patients with immature stroma had worse 5‐year survival compared to patients with mature stroma [adjusted hazard ratio (HR) = 1.32, 95% confidence interval (CI) = 1.06–1.64]. Stromal maturity was significantly associated with 5‐year survival in intestinal‐type subgroup (adjusted HR = 0.63, 95% CI = 1.20–2.21), but not in the diffuse‐type subgroup (adjusted HR = 1.21, 95% CI = 0.87–1.70). Conclusions: Stromal maturity is an independent prognostic factor in gastric adenocarcinoma, and it can be analysed with moderate reproducibility

Tertiary lymphoid structures and gastric cancer prognosis

Abstract Tertiary lymphoid structures (TLSs) are part of immune response against cancer. Their high density and high diameter have been shown to be associated with prognosis in different cancer types. The aim of this study was to examine the prognostic significance of TLS density and diameter in gastric cancer and reproducibility of their assessments. TLS densities and maximal TLS diameter were assessed from hematoxylin–eosin (HE) stained slides of 721 surgically treated gastric cancer patients from two hospitals in Finland. Mortality hazard ratios (HRs) for TLS densities and maximal TLS diameter were analyzed. TLS densities and maximal TLS diameter were assessed with moderate interobserver agreement (Cohen’s kappa 0.50–0.62). Maximal TLS density was not associated with survival (adjusted HR 0.85, 95% CI 0.70–1.02) and neither was hotspot TLS density (adjusted HR 0.85, 95% CI 0.70–1.02). High maximal TLS diameter was associated with longer survival in overall study population (adjusted HR 0.74, 95% CI 0.61–0.89) and in diffuse type subgroup (adjusted HR 0.65, 95% CI 0.50–0.85). In conclusion, high maximal TLS diameter is associated with improved survival in gastric cancer and can be assessed from HE-stained slides. Its prognostic value might be limited to diffuse histological type

Immune cell infiltrate and prognosis in gastric cancer

Abstract Purpose: To examine and compare the prognostic value of immune cell score (ICS) and Klintrup–Mäkinen (KM) grade in gastric cancer. Methods: Gastric adenocarcinoma tissues from samples of 741 patients surgically treated in two hospitals in Finland were assessed for ICS and KM grade. Cox regression with adjustment for confounders provided hazard ratios (HRs) and 95% CIs. Subgroup analyses were performed in intestinal and diffuse type subgroups. The primary outcome was 5-year overall survival. Results: High ICS was associated to longer 5-year survival (adjusted HR 0.70, 95% CI 0.52–0.94), compared to low ICS. The difference was significant in intestinal type subgroup (adjusted HR 0.54, 95% CI 0.36–0.81) but not in diffuse type subgroup (adjusted HR 0.92, 95% CI 0.58–1.46). High KM grade was an independent prognostic factor for longer 5-year overall survival (adjusted HR 0.59, 95% CI 0.45–0.77) in both intestinal (adjusted HR 0.61, 95% CI 0.44–0.85) and diffuse subgroups (adjusted HR 0.52, 95% CI 0.31–0.86). ICS and KM grade were moderately correlated (ρ = 0.425). When both immune cell score and KM grade were included in the regression analysis, only KM grade remained prognostic. Conclusions: Both ICS and KM grade are prognostic factors in gastric adenocarcinoma, but immunohistochemistry-based ICS might not have additional prognostic value over hematoxylin–eosin-based KM grade