Background and Objectives
Gastric cancer (GC) has recently been categorized in molecular subtypes, which include Epstein‐Barr (EBV)‐positive and microsatellite instability (MSI) tumors. This ...distinction may provide prognostic information and identifies therapeutic targets. The aim of this study was to evaluate EBV, MSI, and PD‐L1 immunoexpression in GC and its relationship with clinicopathological characteristics and patient's prognosis.
Methods
We evaluated 287 GC patients who underwent D2‐gastrectomy through immunohistochemistry for DNA mismatch repair proteins and PD‐L1, and in situ hybridization for EBV detection utilizing tissue microarray.
Results
EBV‐positive and MSI were identified in 10.5% and 27% of the GCs, respectively. EBV positivity was associated to male gender (P = 0.032), proximal location (P < 0.001), undetermined Lauren type (P < 0.001), poorly differentiated histology (P = 0.043) and severe inflammatory infiltrate (P < 0.001). MSI‐tumors were associated to older age (P = 0.002), subtotal gastrectomy (P = 0.004), pN0 (P = 0.024) and earlier TNM stage (P = 0.020). PD‐L1‐positive was seen in 8.8% of cases, with predominant expression in EBV‐positive GC (P < 0.001). MSI was associated to better survival outcomes.
Conclusion
EBV‐positive GCs had increased PD‐L1 expression, while MSI GC had better survival outcome. EBV and MSI subgroups are distinct GC entities, their recognition is feasible by conventional techniques, and it may help individualize follow‐up and guide adjuvant therapy.
Beef cattle are key contributors to meat production and represent critical drivers of the global agricultural economy. In Brazil, beef cattle are reared in tropical pastures and finished in feedlot ...systems. The introduction of cattle into a feedlot includes a period where they adapt to high-concentrate diets. This adaptation period is critical to the success of incoming cattle, as they must adjust to both a new diet and environment. Incoming animals are typically reared on a variety of diets, ranging from poor quality grasses to grazing systems supplemented with concentrate feedstuffs. These disparate pre-adaptation diets present a challenge, and here, we sought to understand this process by evaluating the adaptation of Nellore calves raised on either grazing on poor quality grasses (restriction diet) or grazing systems supplemented with concentrate (concentrate diet). Given that nutrient provisioning from the diet is the sole responsibility of the ruminal microbial community, we measured the impact of this dietary shift on feeding behavior, ruminal fermentation pattern, ruminal bacterial community composition (BCC), and total tract digestibility. Six cannulated Nellore bulls were randomly assigned to two 3 × 3 Latin squares, and received a control, restriction, or concentrate diet. All cohorts were then fed the same adaptation diet to mimic a standard feedlot. Ruminal BCC was determined using Illumina-based 16S rRNA amplicon community sequencing. We found that concentrate-fed cattle had greater dry matter intake (
P
< 0.01) than restricted animals. Likewise, cattle fed concentrate had greater (
P
= 0.02) propionate concentration during the adaptation phase than control animals and a lower Shannon’s diversity (
P
= 0.02), relative to the restricted animals. We also found that these animals had lower (
P
= 0.04) relative abundances of
Fibrobacter succinogenes
when compared to control animals during the pre-adaptation phase and lower abundances of bacteria within the
Succinivibrio
during the finishing phase, when compared to the control animals (
P
= 0.05). Finally, we found that animals previously exposed to concentrate were able to better adapt to high-concentrate diets when compared to restricted animals. Our study presents the first investigation of the impact of pre-adaptation diet on ruminal BCC and metabolism of bulls during the adaptation period. We suggest that these results may be useful for planning adaptation protocols of bulls entering the feedlot system and thereby improve animal production.
Feed additives such as monensin (MON) and virginiamycin (VM) are commonly utilized in feedlot diets to enhance rumen fermentation. Nevertheless, the precise effects of combining MON and VM during ...specific feedlot periods and the advantages of this combination remain unclear. This study was designed to investigate the effects of withdrawal of MON when associated with VM during the adaptation and finishing periods on ruminal metabolism, feeding behavior, and nutrient digestibility in Nellore cattle. The experimental design was a 5 × 5 Latin square, where each period lasted 28 days. Five rumen-cannulated Nellore yearling bulls were used (414,86 ± 21,71 kg of body weight), which were assigned to five treatments: (1) MON during the entire feeding period; (2) VM during the entire feeding period; (3) MON + VM during the adaptation period and only VM during the finishing period 1 and 2; (4) MON + VM during the entire feeding period; (5) MON + VM during the adaptation and finishing period 1 and only VM during the finishing period 2. For the finishing period 1, animals fed T3 had improved potential degradability of dry matter (
= 0.02). Cattle fed T3 and T5 had the highest crude protein degradability when compared to animals receiving T2 (
= 0.01). Animals fed T2 and T3 had reduced the time (
< 0.01) and area under pH 6.2 (
= 0.02). Moreover, animals fed T4 had greater population of protozoa from the genus
(
= 0.04) when compared to those from animals fed T2, T3 and T5. For the finishing period 2, animals fed T3 had greater starch degradability when compared to animals receiving T4 and T5 (
= 0.04). Animals fed T3, T4 and T5 had increased the duration of time in which pH was below 5.6 (
= 0.03). The area under the curve for ruminal pH 5.2 and pH 5.6 was higher for the animals fed T3 (
= 0.01), and the area under pH 6.2 was higher for the animals fed T3 and T5 (
< 0.01) when compared to animals receiving T2. There is no substantial improvement on the rumen fermentation parameters by the concurrent utilization of MON and VM molecules, where the higher starch and protein degradability did not improve the rumen fermentation.
Feedlot cattle are usually adapted to high-concentrate diets containing sodium monensin (MON) in more than 14 days. However, considering that the dry matter intake DMI is usually lower during ...adaptation when compared to the finishing period, the use of MON during adaptation may decrease even further the DMI, and virginiamycin (VM) may be an alternative. This study was designed to investigate the effects of shortening the adaptation length from 14 to 9 or 6 days on ruminal metabolism, feeding behavior, and nutrient digestibility of Nellore cattle fed high-concentrate diets containing only VM as the sole feed additive. The experimental design was a 5 × 5 Latin square, where each period lasted 21 days. Five 17 mo-old Nellore yearling bulls were used (415 ± 22 kg of body weight), which were assigned to five treatments: (1) MON (30 mg/kg) and adaptation for 14 days; (2) MON (30 mg/kg) + VM (25 mg/kg) and adaptation for 14 days; (3) VM (25 mg/kg) and adaptation for 14 days; (4) VM (25 mg/kg) and adaptation for 9 days, and (5) VM (25 mg/kg) and adaptation for 6 days. A quadratic effect for adaptation length when only VM was fed was observed for mean pH (
= 0.03), duration of pH below 5.2 (
= 0.01) and 6.2 (
= 0.01), where cattle consuming VM adapted for 9 days had higher mean pH and shorter period of pH below 5.2 and 6.2. Cattle that consumed only MON had a lower concentration of butyrate (
= 0.02) and a higher concentration of propionate (
= 0.04) when compared to those consuming VM and adapted for 14 days. As the adaptation length decreased for animals consuming only VM, the rumen degradability of dry matter (
< 0.01), neutral detergent fiber (
< 0.01), and starch (
< 0.01) decreased; however, protozoa numbers of
and total protozoa increased. It is not recommended to shorten the adaptation length of these animals to either 6 or 9 days without negatively impacting nutrient disappearance and ruminal fermentation patterns.
Feed additives such as monensin (MON) and virginiamycin (VM) are widely used in feedlots diets to maximize rumen fermentation. However, the knowledge about the effects of MON and VM combinations in ...specifics feedlot periods and the benefits of this association are still unclear. This study aimed to evaluate the effects of withdrawal of MON when associated with VM during the adaptation and finishing periods on feedlot performance of Nellore cattle. The experiment was designed as a completely randomized block replicated six times (four animals/pen) in which 120 Nellore bulls (378.4 ± 24.4 kg) were allocated in 30 pens and fed for 112 days according to the following treatments: (T1) MON during the entire feeding period; (T2) VM during the entire feeding period; (T3) MON+VM during the adaptation period and only VM during the finishing period 1 and 2; (T4) MON+VM during the entire feeding period; (T5) MON+VM during the adaptation and finishing period 1 and only VM during the finishing period 2. After 112 days on feed, no treatment effect was observed for DMI (
≥ 0.12). However, bulls fed T5 had greater (
= 0.05) final BW and ADG when compared to T1, T2, and T4. Cattle from T3 and T5 groups presented heavier HCW (
= 0.05) than that fed T1, T2, and T4. Nellore bulls fed T1 and T5 had lower (
< 0.01) DMI variation than those receiving T2. The withdrawal of MON when associated with VM during the final third of the feedlot period improved overall final BW, ADG, and HCW when compared to bulls fed either MON or VM, but did not positively impact feedlot performance when compared to cattle that had MON withdrawn at the end of the adaptation period.
Feedlot cattle are usually adapted to high-concentrate diets containing sodium monensin (MON) in more than 14 days. However, for finishing diets with lower energy content, the use of MON during ...adaptation may hold dry matter intake (DMI), and virginiamycin (VM) may be an alternative. This study was designed to determine the potential of shortening the adaptation of Nellore cattle to high-concentrate diets using only VM as a sole feed additive relative to feedlot performance, feeding behavior, and ruminal and cecum morphometrics. The experiment was designed as a completely randomized block replicated six times (four animals/pen) in which 120 Nellore bulls (390.4 ± 19.0 kg) were fed in 30 pens for 111 days according to the following treatments: (1) MON and adaptation for 14 days (MON14), (2) MON + VM and adaptation for 14 days (MONVM14), (3) VM and adaptation for 14 days (VM14), (4) VM and adaptation for 9 days (VM9), and (5) VM and adaptation for 6 days (VM6). At the end of the adaptation, 30 animals (
n
= 1 per pen) were randomly slaughtered for rumen and cecum evaluations. The remaining 90 bulls were harvested at the end of the study. No effects of treatments were observed (
P
< 0.10) for final body weight, average daily gain (ADG), and hot carcass weight (HCW). Cattle fed VM14 presented a greater (
P
≤ 0.03) DMI, expressed as percent of body weight (BW), than animals fed either MON14 or MONVM14; however, cattle fed either MON14 or MONVM14 improved (
P
≤ 0.02) the gain-to-feed ratio (G/F) by 10.4 or 8.1%, respectively, when compared to bulls fed VM14. Bulls fed VM14 had smaller (
P
< 0.05) papillae area (0.34 vs. 0.42 cm
2
) and rumen absorptive surface area (28.9 vs. 33.8 cm
2
) than those fed MON14. The shortening of the adaptation period linearly decreased the 12th rib fat (
P
= 0.02) and biceps femoris fat daily gain (
P
= 0.02) of Nellore bulls fed only VM, which linearly decreased the final biceps femoris fat thickness (
P
< 0.01). Feedlot cattle fed VM as a sole feed additive should not be adapted to high-concentrate diets in less than 14 days. Regardless of either adaptation length or feed additive, feedlot cattle need at least 14 days to adapt to finishing diets.
Background
Gastric cancer (GC) with microsatellite instability (MSI) is a less aggressive disease and associated with resistance to 5‐fluorouracil (5‐FU)‐based chemotherapy (CMT). Thymidylate ...synthase (TS) is inhibited by 5‐FU, and another potential mediator of therapeutic resistance to 5‐FU. Therefore, we aimed to analyze the association between MSI and TS expression in GC, and its impact on disease outcomes.
Methods
We retrospectively evaluated GC who underwent D2‐gastrectomy. MSI and TS were analyzed by immunohistochemistry. We also investigated p53 expression, PD‐L1 status, and tumor‐infiltrating lymphocytes (CD4 and CD8).
Results
Out of 284 GC, 60 (21.1%) were MSI. Median TS‐score for all cases was 16.5. TS expression was significantly higher in MSI compared to microsatellite‐stable (MSS; p < 0.001). Considering both status, GC were classified in four groups: 167 (58.8%) MSS + TS‐low; 57 (20.1%) MSS + TS‐High; 24 (8.5%) MSI + TS‐low; and 36 (12.7%) MSI + TS‐high. MSI + TS‐high group had less advanced pTNM stage, higher CD8+T cells levels (p < 0.001) and PD‐L1 positivity (p < 0.001). Normal p53 expression was related to MSI GC (p < 0.001). Improved survival was observed in MSI + TS‐high, but no survival benefit was seen with CMT.
Conclusion
MSI GC was associated with high TS levels, which may explain therapeutic resistance to 5‐FU. Additionally, MSI + TS‐high showed better survival, but without improvement with CMT.
Aims
To compare Carnoy's solution (CS) and 10% neutral buffered formalin solution (NBF) as tissue fixatives in colorectal cancer specimens.
Methods and results
Surgical specimens from patients with ...colorectal cancer were analysed. Three groups were studied, as follows: group 1 consisted of 16 paired samples fixed in CS and NBF; and groups 2 and 3 consisted of 14 prospective and 80 retrospective samples, respectively, both randomized for fixation in CS or NBF. Groups 1 and 2 were analysed for amount, quality and integrity of DNA. Morphological analysis, including some of the usual special stains and polymerase chain reaction (PCR), were also performed for group 1, and Sanger sequencing for group 2. Immunohistochemical (IHC) reactions for mismatch repair proteins were studied in groups 1 and 3. Fixative performances were similar for morphology, special stains, and IHC reactions, as well as for the amount, quality and integrity of extracted DNA. PCR amplification was not possible in two cases from CS group 1. Sanger sequencing gave conclusive results for the CS samples tested.
Conclusions
Carnoy's solution and NBF are equivalent fixatives for colorectal cancer specimens and are adequate for routine utilization in surgical and molecular pathology.
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