Nutritional and inflammatory indicators differ among patients with colorectal cancer with distinct microsatellite stability statuses

Abstract

BACKGROUND

Nutritional and inflammatory indicators are crucial in assessing the nutritional health and immune function of patients with cancer, which are factors closely associated with the diagnosis and treatment of colorectal cancer (CRC).

AIM

To explore the relationship between nutritional and inflammatory indicators and microsatellite stability (MSS) status in CRC.

METHODS

The clinical data of 56 patients who underwent surgical treatment for CRC were collected. Furthermore, the expressions of nutritional (levels of serum albumin, triglycerides, serum cholesterol, and body mass index) and inflammatory response indicators (absolute neutrophil count, absolute lymphocyte count, absolute monocyte count, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio) as well as their correlation with microsatellite instability (MSI) status were investigated in patients with CRC.

RESULTS

Compared to the patients with MSS tumors, those with MSI tumors demonstrated significantly lower levels of two nutritional indicators, namely serum albumin and body mass index (P < 0.05). Moreover, patients in the MSI group demonstrated significantly lower absolute lymphocyte counts and higher neutrophil-to-lymphocyte ratio than those in the MSS group (P < 0.05), indicating pronounced differences in inflammatory responses and immune states between the two groups.

CONCLUSION

Certain nutritional and inflammatory indicators exhibit significant differences among patients with MSI and MSS CRC, highlighting their potential role in the clinical treatment and health management of this specific population.

Key Words: Colorectal cancer; Microsatellite instability; Nutritional indicators; Tumor markers; Inflammatory indices; Diagnosis

Core Tip: Our study of 56 patients with colorectal cancer revealed significant correlations between microsatellite instability status and nutritional and inflammatory markers. Compared to microsatellite stability tumors, high microsatellite instability tumors were associated with lower values of serum albumin, body mass index, and higher neutrophil-to-lymphocyte ratio, underscoring the distinct immunological and inflammatory profiles in patients with these two tumor types.

INTRODUCTION

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths and the third most common cancer worldwide. Several developing countries have demonstrated a rapid increase in CRC incidence and mortality rates, while developed countries have exhibited a stable or decreasing trend in these rates[1]. The associated high-risk factors of CRC include adenoma, inflammatory bowel disease, obesity, and Western dietary habits (such as dietary fiber deficiency and high fat-protein intake); however, numerous other causes of this cancer remain unclear. Furthermore, patients with CRC have been shown to have varying prognoses. Previous studies have shown that the prognosis of patients with CRC is related to certain factors, including chromosome instability, CpG island methylator phenotype, and deficient mismatch repair (MMR) mechanisms[2]. Moreover, patients with CRC may have certain differences in their tumor characteristics. Compared to chromosome instability tumors, microsatellite instability (MSI) tumors are typically located in the proximal colon and have poor differentiation, with a high proportion of tumor-infiltrating lymphocytes and peritumoral Crohn’s-like reaction. They are less likely to metastasize to the lymph nodes and distant sites, thereby conferring a better prognosis[3]. Therefore, identifying the heterogeneity of patients with different CRC types and possible causes has great clinical value in providing accurate diagnosis and treatment for this population.

Tumor cells have specific DNA regions known as microsatellite repeats that frequently undergo replication errors. These regions can comprise single nucleotide, dinucleotide, or higher-order nucleotide repeats. Due to their structural characteristics, microsatellite repeats are susceptible to replication slippage during DNA synthesis, resulting in the failed activation of polymerase and ultimately accumulating mutations. The most common microsatellite-related errors are base mismatches, along with insertions and deletions caused by DNA structural issues. In cases where the first nucleobase and template chain are displaced and incorrectly re-paired in the microsatellite region, unpaired nucleobases appear and form a mismatched region. Additionally, the insertions or deletions in the microsatellite region of the DNA encoding area generate frameshift mutations that create abnormal proteins[4]. MSI is a phenomenon where the length of microsatellite sequences is altered owing to the failure of the MMR system to correct the mismatches and insertions/deletions.

Normal cells have a mechanism known as the MMR system, which is highly conserved in bacteria and humans. The MMR system is responsible for monitoring and correcting microsatellite errors by identifying and repairing abnormalities in DNA replication. MutL homolog 1, mutS homolog 2 (MSH2), MSH6, and postmeiotic segregation increased 2 are the primary proteins involved in the MMR system, which interact in the form of heterodimers[5]. In some patients with CRC, the MMR system may be impaired, causing failure to repair these errors promptly[4]. MSI, which is a typical feature of genetic instability in certain types of CRCs, is closely associated with tumor development and is one of the crucial cancerous pathways used to identify colon cancer[6]. High MSI (MSI-H) tumors account for approximately 10%-15% of all CRCs[7]. These tumors are also associated with hereditary non-polyposis CRC (Lynch syndrome), which represents approximately 3% of CRCs[8].

Inflammation is known to play a critical role in the development, progression, prognosis, and treatment outcomes of various cancers[9-11]. Tumor cells stimulated in the inflammatory medium can maintain their growth, invasion, and migration, as well as recruit inflammatory cells by releasing various inflammatory and chemotactic factors. These recruited inflammatory cells are influenced by different inflammatory mediators, resulting in variations in their quantity and function, which, in turn, determines their role in tumor cells[12]. Cytokines produced by neutrophilic granulocytes promote tumor development, vascular formation, tumor progression, and metastasis[13]. In contrast, lymphocytes, especially tumor-infiltrating lymphocytes, exert anti-proliferative and anti-metastatic effects on tumor cells[14,15]. Consequently, reduced lymphocyte count in peripheral blood and tumor tissue is associated with tumor progression and poor prognosis. Mononuclear cells can influence the tumor microenvironment through varied mechanisms, including inducing immune tolerance and vascular formation as well as enhancing tumor cell proliferation; conversely, they also play an anti-tumor role by producing a tumor-killing medium and stimulating natural killer cells[16]. However, the effect of platelets on tumor proliferation and metastasis remains unclear. Previous studies have shown that increased neutrophil-to-lymphocyte ratio (NLR) in patients with solid organ cancer is associated with increased mortality in several malignant tumors[17,18]. Moreover, the increased lymphocyte-to-platelet ratio and C-reactive protein/albumin ratio and the decreased lymphocyte-to-monocyte ratio (LMR) are linked to a poor prognosis[19,20]. In most patients with malignant tumors, inflammatory reactions arise due to the characteristics of poorly differentiated tumor cells and their rapid proliferation. This proliferation can lead to a heightened nutritional depletion status in patients with tumors, significantly affecting their nutritional indicators[21,22]. The inflammatory response and nutritional status of patients are considered vital indicators of tumor formation and development processes, with studies indicating that tumor development generates inflammatory factors that influence prealbumin synthesis in the patients[23]. Additionally, the inflammatory factors during tumor development may have a certain effect on proteins; however, the relationship between these factors and MSI is still uncertain. Therefore, this study aims to investigate the association of nutritional and inflammatory indicators with MSI and to identify the indicators reflecting the tumor status and MSI of patients with CRC.

MATERIALS AND METHODS

Study patients

A total of 56 patients diagnosed with CRC in Nanjing Medical University Affiliated Suzhou Hospital between January 2020 and January 2024 were randomly selected. Collected information included complete clinical case information and follow-up clinical data of the patients who received surgical treatment for CRC. The clinical data of all 56 patients were collected through the electronic medical history system of the hospital, with the acquired data encompassing the levels of preoperative carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), serum albumin, fasting blood glucose, triglycerides, and serum cholesterol, as well as neutrophil, lymphocyte, and monocyte counts. All patients were admitted to the hospital for a week for a complete cardiopulmonary examination to evaluate cardiopulmonary function. Colonoscopy, full abdominal computed tomography, and enhanced magnetic resonance imaging examination of the pelvic cavity were conducted to determine whether the tumor was accompanied by distant metastases. Furthermore, the same surgical team performed a radical resection for CRC. Specifically, patients with colon cancer underwent radical resection, whereas those with rectal cancer were managed with Dixon’s or Miles’ procedure based on their condition.

Tumor-node-metastasis (TNM) staging of the postoperative CRC tissue pathology results was conducted according to the CRC (TNM) segmentation system (2017) of the American Cancer Federation/International Counter-Cancer Union. The patient inclusion criteria were as follows: (1) Preoperative colonoscopy with histological verification of colorectal carcinoma via endoscopic biopsy; (2) Laparoscopic radical resection for colorectal carcinoma; (3) Absence of prior radiotherapy or chemotherapy; (4) Retrieval of at least 12 lymph nodes; (5) Postoperative histopathological confirmation of colorectal carcinoma; (6) Suitable for immunohistochemical assessment of MMR proteins; (7) Biochemical profiles of fasting venous blood samples and hematologic tests on initial hospital admission; and (8) No comorbid hematological disorders, autoimmune conditions, or additional malignancies at other sites. The patient exclusion criteria were as follows: (1) Synchronous or metachronous multicentric cancers; (2) Infectious diseases or fever symptoms within the 3-week preoperative period; (3) Prominent medical comorbidities such as congestive heart failure, renal insufficiency, or respiratory failure before surgery; (4) Incomplete clinical records; or (5) Administration of neoadjuvant therapy before surgery.

Collection of biochemical parameters

Samples for measuring fasting blood glucose were obtained on the morning of the second day following hospital admission and analyzed in the hospital laboratory. Complete blood count, including neutrophil, lymphocyte, and monocyte counts, was acquired using an automated hematology analyzer (CAL 8000 series, Shenzhen Mindray Bio-Medical Electronics Co., Ltd.). Subsequently, the NLR and LMR were derived from these values. Furthermore, the concentrations of CEA and CA19-9 were quantitatively analyzed utilizing an electrochemiluminescence immunoassay system (Cobase 601, Shanghai Roche Pharmaceuticals Co., Ltd.). A CEA level below the threshold of 5 ng/mL and a CA19-9 level of < 27 U/mL were considered within the normal reference range.

Statistical analysis

Data analysis was conducted using IBM SPSS software version 27.0. Frequencies and proportions were expressed as percentages and compared using the χ²-test for categorical variables. Continuous variables were presented as mean ± SD, and group differences were assessed using the independent samples t-test. Correlations between tumor markers and inflammatory indices in relation to TNM staging were evaluated through the Spearman rank correlation coefficient test. Statistical significance was defined as a P value of < 0.05.

RESULTS

This study included a cohort of 56 patients diagnosed with CRC, among which 28 had tumors with the microsatellite instability (MSI) phenotype and 28 had tumors with the microsatellite stability (MSS) phenotype. All patients received surgical interventions in the Affiliated Suzhou Hospital of Nanjing Medical University after a preoperative period of 1 week involving blood routine and biochemical profile tests. The expression levels of four principal MMR proteins (MLH1, MSH2, MSH6 and PMS2) in the CRC tissue samples were evaluated using immunohistochemical methods.

Analysis of general patient information

No significant differences in gender, age, or degree of differentiation were found between the MSI and MSS groups (P > 0.05). However, the MSI group demonstrated a significantly lower number of lymph node metastases than the MSS group (P < 0.05). Among the patients with lymph node metastasis, those in the MSI group showed significantly larger tumor sizes than those in the MSS group (P < 0.05). The MSI group also exhibited a significantly lower TNM stage than the MSS group (P < 0.05) (Table 1).

Table 1 Definitions of some specific terms, n (%).

Clinical indicators	MSI (n = 28)	MSS (n = 28)	P value
Gender			1.000
Male	15 (53.57)	15 (53.57)
Female	13 (46.43)	13 (46.43)
Age, years	67.39 ± 12.470	63.75 ± 11.407	0.259
Tumor size			0.010
≥ 5 cm	18 (64.29)	6 (21.43)
< 5 cm	10 (35.71)	22 (78.57)
Lymph node metastases			0.008
Degree of differentiation			0.412
Stage			0.019
≤ stage II	21 (75.00)	6 (21.43)
> stage II	7 (25.00)	22 (78.57)

MSI: Microsatellite instability; MSS: Microsatellite stability.

Analysis of nutritional indices

No significant differences were observed in the fasting blood glucose, triglycerides, or serum cholesterol levels between the two groups (P > 0.05). Patients in the MSI group demonstrated significantly lower levels of serum albumin (P = 0.002) and body mass index (BMI) (P = 0.011) than those in the MSS group (Table 2), indicating a compromised nutritional status in the MSI group.

Table 2 Analysis of nutritional indices, mean (range).

Nutritional indices	MSI (n = 28)	MSS (n = 28)	P value
Fasting blood glucose	5.93 (3.95-11.77)	6.38 (4.66-9.91)	0.330
Triglyceride	1.16 (0.40-3.29)	1.14 (0.39-2.40)	0.851
Serum cholesterol	4.19 (2.64-5.86)	4.69 (2.95-7.09)	0.054
Serum albumin	33.95 (24.86-48.50)	38.92 (23.70-47.22)	0.002
BMI	22.15 (14.22-29.07)	24.80 (17.75-31.89)	0.011

MSI: Microsatellite instability; MSS: Microsatellite stability; BMI: Body mass index.

Analysis of inflammatory indices

No significant group differences were noted in the absolute neutrophil count, absolute monocyte count, or LMR (P > 0.05). The MSI group showed a higher NLR than the MSS group (P = 0.014) (Table 3), suggesting a heightened inflammatory response among the patients in the MSI group. Furthermore, the MSI group was found to have a significantly lower absolute lymphocyte count than the MSS group (P = 0.02) (Table 3), highlighting the potential underlying immune deficiency within the patients in the MSI group.

Table 3 Analysis of inflammatory indices, mean (range).

Inflammatory indices	MSI (n = 28)	MSS (n = 28)	P value
Neutrophil count	4.89 (1.45-12.01)	3.92 (2.01-6.07)	0.065
Lymphocyte count	1.37 (0.65-2.19)	1.66 (0.74-2.80)	0.020
Monocyte count	0.46 (0.21-0.82)	0.41 (0.22-0.81)	0.152
NLR	3.88 (1.24-13.05)	2.57 (1.00-4.74)	0.014
LMR	3.48 (1.20-8.76)	4.24 (2.14-7.36)	0.097

MSI: Microsatellite instability; MSS: Microsatellite stability; NLR: Neutrophil-to-lymphocyte ratio; LMR: Lymphocyte-to-monocyte ratio.

Analysis of tumor markers

A comparative analysis of the preoperative CEA and CA19-9 levels between the two groups also revealed no significant differences (P > 0.05) (Table 4). Nevertheless, these tumor markers are crucial for assessing tumor load and prognosis[24]. The analysis was conducted using the same methodology.

Table 4 Analysis of tumor markers, mean (range).

Tumor markers	MSI (n = 28)	MSS (n = 28)	P value
Preoperative CEA	25.57 (0.49-577.52)	17.06 (1.00-170.22)	0.695
Preoperative CA19-9	35.58 (2.00-439.00)	60.20 (5.02-870)	0.475

MSI: Microsatellite instability; MSS: Microsatellite stability; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9.

DISCUSSION

Previous studies have shown that MSI-H solid tumors exhibit better responses to immune checkpoint inhibitors (ICIs) and that inflammation markers in the body can be used to predict ICI responses[25-27]. These investigations have demonstrated improved responses to ICI treatment in patients with solid organ tumors accompanied by highly systemic inflammation[28]. The current study revealed a significant association between MSI and systemic inflammatory responses, implying that CRCs with MSI-H elicit an elevated systemic inflammatory reaction. Prior research has also reported that the nutritional status of patients with CRC may significantly affect their survival. Specifically, nutritional risk and moderate-to-severe malnutrition were associated with an increased mortality risk in patients with CRC[29].

Patients with MSI-H CRC are more sensitive to ICIs[28]. Nutritional status, which is a crucial factor affecting the immune status of patients, may indirectly influence the immunotherapy response of those with MSI CRC. Moreover, a good nutritional status can enhance the immune response of patients, a particularly critical factor in those with MSI-H CRC. In line with this notion, studies have shown that immunonutrition interventions can improve the nutritional status and immune function of patients with CRC. For example, combination therapy of ICIs and treatments with other mechanisms of action for patients with MSS or proficient MMR CRC was found to improve efficacy. Good nutritional status may play a role in this intervention strategy by enhancing the overall health status and treatment tolerance of patients[30]. Although extensive research has been conducted on inflammatory response indicators, MSI, and pathological features in CRC, scarce studies have examined the interplay among inflammatory markers, nutritional indicators, and MSI in this cancer. Our study analyzed the correlation between MSI expression, inflammatory indicators, and nutritional indicators in patients with CRC, revealing a notable association among these factors.

In this research, we explored the relationship of MSI with nutritional and inflammatory indicators among patients with CRC. Our analysis identified pronounced disparities in nutritional indicators between the MSI and MSS groups. In particular, patients in the MSI group demonstrated reduced levels of serum albumin and BMI, indicating that this group had a compromised nutritional profile compared to those with MSS tumors. Additionally, the MSI group had lower lymphocyte counts and higher NLR than those of the MSS group, suggesting distinct inflammatory and immunological profiles between these two patient groups. These differences in nutritional and inflammatory indicators between the patients with MSS and MSI CRCs underscored their applicability as diagnostic markers for MSI in oncology.

We also investigated the variations in inflammatory indicators in relation to MSI among patients with CRC. Our initial findings demonstrated that CRC with MSI was correlated with elevated levels of chronic inflammatory markers, while the NLR was comparatively higher in the MSI group than in the MSS group. However, our results were inconsistent with the findings reported in a study by Karaoğlan et al[31]. Although that study found additional correlations between MSI status and inflammatory reactions, no statistically significant variations were detected in terms of the NLR.

The distinct inflammatory responses between the patients with MSI and MSS CRCs may stem from variations in their tumor microenvironments and immune conditions. MSI-H tumors demonstrate unique inflammatory characteristics and greater immune response activity within the tumor microenvironment than MSS tumors[31]. Due to deficiencies in DNA MMR, MSI-H tumors accumulate a higher mutational burden, leading to the increased production of immunogenic neoantigens and a stronger immune response. This heightened immune response may mitigate the negative effects of chronic inflammation within the tumor microenvironment. In contrast, MSS tumors have a lower mutational burden, and thus produce fewer neoantigens and a relatively weaker immune response. Patients with MSI-H tumors have a significantly better response to ICIs than those with MSS tumors, and this difference may be related to the extent and severity of immune cell infiltration in the MSI-H tumors[25-27]. In addition, dietary factors are also crucial in the development and progression of CRC and may lead to different inflammatory conditions. Machine learning-based CRC prediction models hold clinical value by enabling more personalized dietary recommendations[32]. Chronic consumption of high-calorie, high-fat diets disrupts the balance of intestinal microbiota and triggers localized inflammation, fostering a microenvironment that promotes CRC development. Evidence suggests that postoperative administration of dietary fiber enhances immune function, alleviates disease-related inflammation, and inhibits tumor proliferation[32], thus contributing positively to patient outcomes. Apart from these potential associations, other distinct biological mechanisms may also influence the inflammatory profiles of patients with MSI and MSS tumors.

In our study, we sought to minimize potential confounding factors by excluding patients with hematological disorders, autoimmune diseases, or additional malignancies at other sites. However, the presence of other comorbidities, may still have influenced the observed nutritional and inflammatory profiles. For example, patients with diabetes often exhibit altered inflammatory markers and nutritional status due to underlying metabolic dysregulation[33]. Likewise, low-grade inflammation has been identified as a potential contributor to the pathogenesis of various cancers[34]. For patients with a stoma, factors such as a history of diabetes, the 2002 Nutritional Risk Screening score, and the Prognostic Nutritional Index are associated with an increased risk of early complications related to stoma formation after CRC surgery[35]. Adherence to an anti-inflammatory dietary pattern should be recommended to reduce incidence of CRC worldwide[34]. To align with recent findings, future studies should systematically incorporate the analysis of dietary factors and inflammatory markers into comprehensive assessment and management strategies for CRC, ensuring that these factors are integrated within clinical practice and patient health management frameworks.

Furthermore, we did not find any disparities in the levels of tumor markers (i.e., preoperative CEA and CA19-9) between the two groups. This absence of variation in tumor marker concentration could be ascribed to the complex interplay of multiple factors during oncogenesis, with MSI status potentially being one of the numerous factors affecting tumor indices. For example, the tumor microenvironment might play distinct roles in MSS and MSI tumors. However, these roles might not be explicitly manifested in the fluctuations of tumor marker levels. Therefore, more profound research is warranted to precisely elucidate the possible reasons for the lack of tumor marker differences between patients with MSI and MSS tumors.

Our study has several inherent limitations that should be considered. One of the shortcomings was that this study had a restricted sample size focused on specific tumor types, which potentially hindered a holistic comprehension of the interplay between inflammatory biomarkers and MSI status. Subsequent studies should encompass a more diverse spectrum of tumor types and utilize more refined techniques to detect MSI, such as polymerase chain reaction, instead of relying exclusively on immunohistochemistry analysis. More profound and exhaustive research can be facilitated by augmenting the sample size, enhancing follow-up data, investigating the underlying mechanisms, and strengthening the relevant evidence. Our study outcomes offer directional guidance for the clinical stratification and personalized treatment of patients with CRC. Furthermore, conclusions from the present research underscore the significance of evaluating MSI status in patients with CRC and provide valuable insights for developing tailored therapeutic approaches in the future.

CONCLUSION

In this study, we comprehensively analyzed patients with MSI and MSS CRCs and revealed significant nutritional and immunological differences between these two groups. Patients with MSI tumors exhibited significantly lower values in two key nutritional indicators (i.e., serum albumin and BMI) (P < 0.05), indicating a potentially compromised nutritional status in those with this tumor type. Additionally, the patients in the MSI group presented with significantly lower absolute lymphocyte counts and higher NLR than those in the MSS group (P < 0.05), highlighting distinct inflammatory responses and immune states between the two cohorts. All these findings underline the importance of considering MSI status when assessing nutritional health and immune function in patients with CRC, particularly among those in young adulthood, as well as emphasize the need for tailored monitoring and management strategies to achieve optimal health outcomes in such populations.