Integrative Analyses of Colorectal Cancer Show Immunoscore Is a Stronger Predictor of Patient Survival Than Microsatellite Instability.

Microsatellite instability in colorectal cancer predicts favorable outcomes. However, the mechanistic relationship between microsatellite instability, tumor-infiltrating immune cells, Immunoscore, and their impact on patient survival remains to be elucidated. We found significant differences in mutational patterns, chromosomal instability, and gene expression that correlated with patient microsatellite instability status. A prominent immune gene expression was observed in microsatellite-instable (MSI) tumors, as well as in a subgroup of microsatellite-stable (MSS) tumors. MSI tumors had increased frameshift mutations, showed genetic evidence of immunoediting, had higher densities of Th1, effector-memory T cells, in situ proliferating T cells, and inhibitory PD1-PDL1 cells, had high Immunoscores, and were infiltrated with mutation-specific cytotoxic T cells. Multivariate analysis revealed that Immunoscore was superior to microsatellite instability in predicting patients' disease-specific recurrence and survival. These findings indicate that assessment of the immune status via Immunoscore provides a potent indicator of tumor recurrence beyond microsatellite-instability staging that could be an important guide for immunotherapy strategies.

[About 2 cases of ectopic sebaceous glands in esophagus: Endoscopic and histological correlations from biopsies and resected specimens]. / À propos de 2 cas de glandes sébacées ectopiques œsophagiennes : corrélations endoscopiques, et anatomopathologiques sur biopsies et pièces opératoires.

Sebaceous glands are cutaneous annexes located in the dermis. Focal spots of ectopy of these glands are frequently identified in ectodermal tissues: they represent Fordyce's disease. However, only a few cases of ectopic sebaceous glands have been mentioned in non-ectodermic tissue. Fordyce spots of esophageal location are unusual, and most of them have been diagnosed from biopsy specimens. We report two cases of ectopic sebaceous glands in esophagus, the first diagnosed from a resected specimen, the second from biopsies. A literature review is carried out.

Genetic variations of the A13/A14 repeat located within the EGFR 3' untranslated region have no oncogenic effect in patients with colorectal cancer.

BACKGROUND: The EGFR 3' untranslated region (UTR) harbors a polyadenine repeat which is polymorphic (A13/A14) and undergoes somatic deletions in microsatellite instability (MSI) colorectal cancer (CRC). These mutations could be oncogenic in colorectal tissue since they were shown to result into increased EGFR mRNA stability in CRC cell lines. METHODS: First, we determined in a case control study including 429 CRC patients corresponding to different groups selected or not on age of tumor onset and/or familial history and/or MSI, whether or not, the germline EGFR A13/A14 polymorphism constitutes a genetic risk factor for CRC; second, we investigated the frequency of somatic mutations of this repeat in 179 CRC and their impact on EGFR expression. RESULTS: No statistically significant difference in allelic frequencies of the EGFR polyA repeat polymorphism was observed between CRC patients and controls. Somatic mutations affecting the EGFR 3'UTR polyA tract were detected in 47/80 (58.8%) MSI CRC versus 0/99 microsatellite stable (MSS) tumors. Comparative analysis in 21 CRC samples of EGFR expression, between tumor and non malignant tissues, using two independent methods showed that somatic mutations of the EGFR polyA repeat did not result into an EGFR mRNA increase. CONCLUSION: Germline and somatic genetic variations occurring within the EGFR 3' UTR polyA tract have no impact on CRC genetic risk and EGFR expression, respectively. Genotyping of the EGFR polyA tract has no clinical utility to identify patients with a high risk for CRC or patients who could benefit from anti-EGFR antibodies.

Metastatic colorectal cancer KRAS genotyping in routine practice: results and pitfalls.

KRAS genotyping is mandatory before anti-epidermal growth factor receptor monoclonal antibody therapy in metastatic colorectal cancer, which is the second leading cause of cancer-related death in the United States and in Europe. Thus, large-scale KRAS mutation screening is needed for efficient patient management and in the future metastatic colorectal cancer genotyping might also include the detection of the BRAF V600E mutation, which is a very strong negative prognostic factor in colorectal cancer. We report our experience of routine KRAS/BRAF mutation screening practice performed on 1130 formalin-fixed paraffin-embedded tumor samples from 992 colorectal cancer patients. DNA was extracted from macrodissected tumor areas highlighted by a pathologist, KRAS codons 12/13 and BRAF V600E mutations were assessed in a single SNaPshot® multiplex assay and each mutation was confirmed by an independent analysis. KRAS and BRAF mutations were, respectively, present in 41.8 and 6.5% of the tumor samples. If KRAS and BRAF mutations were mutually exclusive, four samples presented two concomitant KRAS mutations. Genotyping of paired primary tumors and metastases from 44 patients indicated that 5 patients (11.4%) presented discordant KRAS mutational status. KRAS genotype heterogeneity was also observed within primary tumor sites in seven cases. Non-reproducible KRAS artefactual mutations were detected in 53 samples (4.7%). We found that the prominent mechanism leading to these artefactual mutations was the fragmentation of DNA occurring during tissue processing. Routine KRAS genotyping performed on formalin-fixed paraffin-embedded tissues requires, therefore, the development of quality control scheme for molecular pathology, especially because of DNA damages induced by formalin fixation. The tumor heterogeneity observed in some patients indicates that it should be more appropriate to perform KRAS genotyping on metastases if sample is available.

Prognostic value of circulating mutant DNA in unresectable metastatic colorectal cancer.

OBJECTIVE: No validated biologic prognostic marker is presently available in metastatic colorectal cancer (MCRC). We prospectively evaluated the prognostic value of circulating mutant DNA in 31 patients presenting an unresectable MCRC treated by chemotherapy, and we used, as tumor markers, KRAS mutations and methylation of the RASSF2A promoter. METHODS: Detection in the serum of KRAS mutation and RASSF2A methylation were performed using sensitive methods, respectively, real-time polymerase chain reaction (PCR) performed in the presence of a peptide nucleic acid specific of the wild-type sequence and methyl-specific PCR after bisulfite treatment. RESULTS: Among 29 MCRC patients for whom DNA from the primary tumor was available, 23 (79%) presented at least one of the markers in their primary tumor, and 12 of them presented the same alteration in serum. For the 2 remaining patients, RASSF2A methylation was detected in serum indicating that this alteration was present in the primary tumor. These 14 patients with a detectable tumor marker in their serum were designed sDNA+ patients. After 6 months of follow-up, 11/14 (79%) sDNA+ and 1/11 (9%) sDNA- patients presented a progressive disease (P = 0.001). The median progression free survival was 5 months in sDNA+ patients versus 14 months in sDNA- patients (P = 0.004). After 1 year of follow-up, 2 of 14 (14%) sDNA+ and 8 of 11 (73%) sDNA- patients presented no signs of disease progression (P = 0.005). CONCLUSIONS: This study suggests that the presence of circulating mutant DNA in unresectable MCRC patients, which can be detected using simple methods such as methylation-specific PCR or real-time PCR, is highly predictive of clinical outcome.

A diet containing whey protein, glutamine, and TGFbeta modulates gut protein metabolism during chemotherapy-induced mucositis in rats.

BACKGROUND: Mucositis, a common side effect of chemotherapy, is characterized by compromised digestive function, barrier integrity and immune competence. AIMS: Our aim was to evaluate the impact of a specifically designed diet Clinutren Protect (CP), which contains whey proteins, TGFbeta-rich casein, and free glutamine, on mucositis in rats. METHODS: Mucositis was induced by three consecutive injections (day 0, day 1, day 2) of methotrexate (2.5 mg/kg). Rats had free access to CP or placebo diets from days -7 to 9. In the placebo diet, whey proteins and TGFbeta-rich casein were replaced by TGFbeta-free casein and glutamine by alanine. Intestinal parameters were assessed at day 3 and 9. Values, expressed as mean +/- SEM, were compared using two-way ANOVA. RESULTS: At day 3, villus height was markedly decreased in the placebo (296 +/- 11 microm) and CP groups (360 +/- 10 microm) compared with controls (464 +/- 27 microm), but more markedly in the placebo as compared to CP group. The intestinal damage score was also reduced in the CP compared with the placebo group. Glutathione content increased in the CP compared with the placebo group (2.2 +/- 0.2 vs. 1.7 +/- 0.2 micromol/g tissue). Gut protein metabolism was more affected in the placebo than in the CP group. The fractional synthesis rate was decreased in the placebo group (93.8 +/- 4.9%/day) compared with controls (121.5 +/- 12.1, P < 0.05), but not in the CP group (106.0 +/- 13.1). In addition, at day 9, rats exhibited improved body weight and food intake recovery in the CP compared to the placebo group. CONCLUSIONS: Clinutren Protect feeding reduces intestinal injury in the acute phase of methotrexate-induced mucositis in rats and improves recovery.

Tumor-infiltrating lymphocytes in colorectal cancers with microsatellite instability are correlated with the number and spectrum of frameshift mutations.

Colorectal cancers with microsatellite instability are characterized by an important density of tumor-infiltrating lymphocytes and a good prognosis. Microsatellite instability results from the inactivation of the DNA mismatch repair system and induces secondary somatic frameshift mutations within target genes harboring repeat sequences in their coding frame. By disrupting the open reading frame, frameshift mutations can result in the appearance of potentially immunogenic neopeptides. To determine the frameshift mutations inducing a T-cell response during the development of a tumor with microsatellite instability, we studied in 61 colorectal cancer patients with microsatellite instability, using a fluorescent multiplex PCR comparative analysis, the relative frequency of frameshift mutations within 19 target genes and analyzed the correlation of these frameshift mutations with the density of CD3+ tumor-infiltrating lymphocytes. The four most frequently mutated genes were ACVR2 (92%), TAF1B (84%), ASTE1/HT001 (80%) and TGFBR2 (77%). The vast majority (95%) of the tumors exhibited at least three frameshift mutations, and the number of frameshift mutations was associated with tumor progression (TNM stage, wall invasion and tumor diameter). Tumor-infiltrating lymphocyte density was associated with the overall number of frameshift mutations and with the presence of frameshift mutations within two target genes, namely ASTE1/HT001 and PTEN. These results strongly argue for the clinical relevance of immunotherapy of colorectal cancers with microsatellite instability.

Chemotherapy-induced mucositis is associated with changes in proteolytic pathways.

Mucositis, a common toxic side effect of chemotherapy, is characterized by an arrest of cell proliferation and a loss of gut barrier function, which may cause treatment reduction or withdrawal. Gut integrity depends on nutritional and metabolic factors, including the balance between protein synthesis and proteolysis. The effects of methotrexate (MTX; a frequently used chemotherapeutic agent) on intestinal proteolysis and gut barrier function were investigated in rats. Male Sprague-Dawley rats received 2.5 mg/kg of MTX subcutaneously during 3 days and were euthanized at Day 4 (D4) or Day 7 (D7). We observed at D4 that MTX induced mucosal damage and increased intestinal permeability (7-fold) and the mucosal concentration of interleukin (IL)-1beta and IL-6 (4- to 6-fold). In addition, villus height and glutathione content significantly decreased. Intestinal proteolysis was also affected by MTX as cathepsin D activity increased at D4, whereas chymotrypsin-like proteasome activity decreased and calpain activities remained unaffected. At D7, cathepsin D activity was restored to control levels, but proteasome activity remained reduced. This disruption of proteolysis pathways strongly contributed to mucositis and requires further study. Lysosomal proteolytic activity may be considered the main proteolytic pathway responsible for alteration of mucosal integrity and intestinal permeability during mucositis, as cathepsin D activity was found to be correlated with mucosal atrophy and intestinal permeability. Proteasome regulation could possibly be an adaptive process for survival. Future investigation is warranted to target proteolytic pathways with protective nutritional or pharmacological therapies during mucositis.

Effects of glutamine supplementation on gut barrier, glutathione content and acute phase response in malnourished rats during inflammatory shock.

AIM: To evaluate the effect of glutamine on intestinal mucosa integrity, glutathione stores and acute phase response in protein-depleted rats during an inflammatory shock. METHODS: Plasma acute phase proteins (APP), jejunal APP mRNA levels, liver and jejunal glutathione concentrations were measured before and one, three and seven days after turpentine injection in 4 groups of control, protein-restricted, protein-restricted rats supplemented with glutamine or protein powder. Bacterial translocation in mesenteric lymph nodes and intestinal morphology were also assessed. RESULTS: Protein deprivation and turpentine injection significantly reduced jejunal villus height, and crypt depths. Mucosal glutathione concentration significantly decreased in protein-restricted rats. Before turpentine oil, glutamine supplementation restored villus heights and glutathione concentration (3.24 +/- 1.05 vs 1.72 +/- 0.46 mumol/g tissue, P<0.05) in the jejunum, whereas in the liver glutathione remained low. Glutamine markedly increased jejunal alpha1-acid glycoprotein mRNA level after turpentine oil but did not affect its plasma concentration. Bacterial translocation in protein-restricted rats was not prevented by glutamine or protein powder supplementation. CONCLUSION: Glutamine restored gut glutathione stores and villus heights in malnourished rats but had no preventive effect on bacterial translocation in our model.

Endoplasmic reticulum stress, unfolded protein response and development of colon adenocarcinoma.

When misfolded proteins accumulate in the endoplasmic reticulum (ER), the cell is said to experience ER stress. This triggers an unfolded protein response (UPR) to restore the balance between misfolded proteins and ER chaperones such as BiP. UPR signalling is required for the growth of many solid cancers. In chronic ER stress, factors including CHOP have been shown to mediate cell death. Colorectal adenocarcinoma arises due to progressive changes within pre-malignant lesions. Our aim was to test the hypothesis that the expression of BiP and CHOP correlates with the progression of those pre-malignant lesions.Eighty-one patients with colon neoplasms treated at Rouen University Hospital between January 1, 2003 and January 1, 2013 were randomly selected. The expression of BiP and CHOP was estimated by immunohistochemical staining of a tissue microarray generated from colon cores: normal tissue, low-grade and high-grade adenoma, invasive colon adenocarcinoma and lymph node metastasis of colon adenocarcinoma. In parallel, nine cases comprising areas from normal epithelium to dyplasia to invasive carcinoma and included in the TMA were analysed on whole sections.As colon epithelium shows increasing evidence of pre-malignant and then malignant changes, BiP expression significantly increases (p for trend < 0.001), whereas CHOP expression is attenuated (p for trend < 0.001).We identified a positive relationship between BiP expression and colon carcinogenesis, and a negative correlation for CHOP expression. These findings are consistent with a model in which ER stress accompanies oncogenesis and in which loss of proteins that mediate the toxicity of ER stress, such as CHOP, may facilitate tumorigenesis. This raises the exciting possibility that restoration of the negative feedback loop of UPR, if achievable, might antagonise the malignant process.

Overexpression of B-type cyclins alters chromosomal segregation.

To identify genes which overexpression results into chromosomal instability (CIN), we developed a biological approach based on a yeast indicator strain in which CIN can be detected by a sectoring phenotype. Screening in this strain of a yeast genomic library cloned into a high copy vector led us to identify, among the clones generating 100% of sectoring colonies, Clb5, one of the six B-type cyclins present in yeast. Overexpression of cyclin B2 and cyclin B1, the two human homologs of Clb5, in the CIN indicator strain resulted also into a sectoring phenotype and induced, like overexpression of Clb5, an abnormal sensitivity to benomyl, indicating that overexpression of B-type cyclins alters the spindle checkpoint. In a series of 38 primary colorectal cancers, we detected in five tumors (13%) an accumulation of cyclin B1, which was neither related to mRNA overexpression nor to mutation within the coding region, and in five other tumors (13%) a 2-10-fold increase of cyclin B2 mRNA which was not related to gene amplification. These results suggest that overexpression of cyclins B, resulting from different mechanisms, could contribute, through an alteration of the spindle checkpoint, to the chromosomal instability observed in cancer.

Correlation between Density of CD8+ T-cell Infiltrate in Microsatellite Unstable Colorectal Cancers and Frameshift Mutations: A Rationale for Personalized Immunotherapy.

Colorectal cancers with microsatellite instability (MSI) represent 15% of all colorectal cancers, including Lynch syndrome as the most frequent hereditary form of this disease. Notably, MSI colorectal cancers have a higher density of tumor-infiltrating lymphocytes (TIL) than other colorectal cancers. This feature is thought to reflect the accumulation of frameshift mutations in sequences that are repeated within gene coding regions, thereby leading to the synthesis of neoantigens recognized by CD8(+) T cells. However, there has yet to be a clear link established between CD8(+) TIL density and frameshift mutations in colorectal cancer. In this study, we examined this link in 103 MSI colorectal cancers from two independent cohorts where frameshift mutations in 19 genes were analyzed and CD3(+), CD8(+), and FOXP3(+) TIL densities were quantitated. We found that CD8(+) TIL density correlated positively with the total number of frameshift mutations. TIL densities increased when frameshift mutations were present within the ASTE1, HNF1A, or TCF7L2 genes, increasing even further when at least one of these frameshift mutations was present in all tumor cells. Through in vitro assays using engineered antigen-presenting cells, we were able to stimulate peripheral cytotoxic T cells obtained from colorectal cancer patients with peptides derived from frameshift mutations found in their tumors. Taken together, our results highlight the importance of a CD8(+) T cell immune response against MSI colorectal cancer-specific neoantigens, establishing a preclinical rationale to target them as a personalized cellular immunotherapy strategy, an especially appealing goal for patients with Lynch syndrome.

PAS inclusions, immunoreactive tenascin and proliferative activity in low-grade chondrosarcomas.

To distinguish between chondrosarcoma (grade 1--borderline histology) and enchondroma, we examined six chondrosarcomas (grade 1--borderline histology) which looked like benign lesions. Their diagnosis, albeit based on clinical, radiologic and pathologic examinations, was not easily reached. Moreover, we examined six enchondromas and 11 chondrosarcomas, the diagnoses of which were straightforward. All cartilaginous tumors were studied, placing emphasis on PAS-positive intracytoplasmic globules. Anti-Ki67 proliferation-associated nuclear antigen antibody and tenascin antibody were applied. The following features were observed in low-grade chondrosarcomas: (1) masses of hyalin and/or myxoid cartilage invading spaces around the tumor, (2) host lamellar bone trabeculae surrounded by cartilage on all sides, (3) tumoral resorption of bone trabeculae. Intracytopasmic hyalin globules (ICG) were more frequently found in malignant than in benign neoplasm (p = 0.042). Moreover, tenascin matrix immunoreactivity was more likely to be observed in benign than in malignant neoplasm (p = 0.029). Ki67 immunoreactivity was more frequent in characterized than in low-grade chondrosarcomas or in enchondromas, where it was null (p = 0.0044).

[Juvenile polyposis coli. The usefulness of a genetic study and the role of surgical treatment]. / Polypose juvénile familiale. Intérêt de l'etude génétique et place du traitement chirurgical.

We report two cases of familial juvenile polyposis coli. SMAD4 gene mutation was found in our two patients, leading to the definite diagnosis. Colonic cancer occurred in the first patient. Long-term outcome was favorable after colectomy. In the second patient, prophylactic total colectomy was performed. Rectal bleeding, diarrhea, stomach obstruction and vomiting developed during the follow-up. Proctectomy, distal partial gastrectomy and total gastrectomy were successively performed.

[Retrorectal cystic hamartomas. Report of one case]. / Hamartome kystique rétrorectal. A propos d'une observation.

Retrorectal cystic hamartomas (RCH) are rare congenital lesions of the presacral space, of which 68 cases are reported under different terms. Clinicopathologic features are usually constant and similar to the present case. A 23-year-old woman complained of abdominal and perineal pains for several months. Physical examination revealed a nodular mass in the posterior part of the rectum. A pelvic MRI showed a 5.5 cm cystic retrorectal mass compressing the rectum. The patient underwent surgical resection. Pathologic examination found an ill-defined nodular mass, composed by numerous cysts surrounded by fibroadipose tissue. Cysts were lined by different epithelia: keratinized and non keratinized squamous, transitional, ciliated and mucus-producing columnar epithelia. Few mucinous glands were noted, connected to some cysts. These epithelial structures were surrounded by connective tissue in which well-differentiated bundles of smooth muscle fibers were present without well-formed muscularis. The RCH differential diagnosis includes principally congenital cysts: epidermal cysts, cystic teratomas, dermoid cysts, anal gland cysts and rectal duplications. An embryologic origin of RCH from remnants of the postanal gut is currently accepted. Loco-regional inflammatory process frequently complicates this lesion and can cause perirectal fistulae. RCH also possesses a malignancy potential, with development of adenocarcinomas. To avoid these complications, complete excision is recommended.

[Recurring bone epithelioid hemangioma]. / Hémangiome épithélioïde osseux récidivant.

Bone vascular tumors are very rare. Epithelioid types are described according to their architecture, their degree of vascular differentiation, and their cytonuclear atypia. The include epithelioid hemangioma, epithelioid hemangioendothelioma, and angiosarcoma. We report a case of L4 corpus vertebral bone epithelioid hemangioma. The patient was a 25-year-old man with a tumor that recurred twice. The lesion was characterized by a vascular lumen lined by cells with regular nuclei and inflammatory infiltrates. Capillaries were lined by prominent epithelioid endothelial cells, associated with CD31+ and cytokeratin-.

[Detection of HHV8 latent nuclear antigen by immunohistochemistry. A new tool for differentiating Kaposi's sarcoma from its mimics]. / Détection de l'antigène LNA1 de l'HHV8 par immunohistochimie.

UNLABELLED: The purpose of this work was to study the value of HHV8 latent nuclear antigen 1 detection by immunohistochemistry in Kaposi sarcoma and its mimics. MATERIALS AND METHODS: : We used the mAB LNA53 against the latent nuclear antigen 1 of HHV8 to study its expression by immunohistochemistry in paraffin embedded biopsy of Kaposi and its mimics. We also performed in vitro PCR for HHV8 DNA, extracted from the same paraffin embedded biopsies. We studied characteristic lesions of 26 Kaposi sarcoma; 20 cutaneous lesions raising problems of differential diagnosis. We also studied 11 biopsies of skin, mucosa, or lymph nodes of patients infected by HHV8 but without Kaposi sarcoma, and 22 lesions initially classified by histological analysis as uncertain Kaposi sarcoma . RESULTS: : In all cases of Kaposi, HHV8 was detected in the majority of tumor cells, with no expression in other adjacent cells. In these biopsies HHV8 DNA, was identified by in vitro PCR. None of the 20 Kaposi sarcoma mimics and the 11 lesions of patients infected by HHV8 but without any Kaposi sarcoma, were HHV8+ on immunohistochemistry sections or by PCR. From the 22 cases of uncertain Kaposi sarcoma, only the 14 lesions HHV8 PCR+ and with a clinical evolution in accordance with a Kaposi sarcoma, were HHV8+ on immunohistochemistry. In contrast, the 8 cases negative for HHV8 on immunohistochemistry were also PCR- and had a self-healing evolution in accordance with the diagnostic of pyogenic granuloma. CONCLUSION: : Detection of the latent nuclear antigen 1 of HHV8 by immunohistochemistry is a specific and sensitive diagnostic tool for differentiating Kaposi sarcoma from its mimics.

[Cytokeratins 7 and 20 immunohistochemistry in ampullary carcinomas]. / Expression immunohistochimique des cytokératines 7 et 20 dans les carcinomes ampullaires.

UNLABELLED: Ampullary carcinomas (AC) account for 33% of all surgically operable pancreatoduodenal tumors. The 5-year relative survival rate is 50% and tumoral stage is the main prognostic factor. However, among the three AC histological subtypes (intestinal, pancreatobiliary and mixed), a favorable prognostic has been reported for the intestinal subtype. BACKGROUND: The aims of this study were to determine the prognostic impact of AC histologic subtype and of cytokeratins (CK) 7 and 20 immunostaining profile in these tumors. PATIENTS AND METHODS: Clinical data of 54 AC were obtained retrospectively. Macroscopic and histologic documents were reviewed and immunostainings for CK7 and CK20 were performed. RESULTS: The classification of tumors, according to histological subtype, was: intestinal 26%, pancreatobiliary 65% and mixed 9%. No correlation was found between histological subtype and tumor stage. The 5-year survival rate varied from 100% for intestinal subtype to 35% for pancreatobiliary subtype. A strong correlation (p < 0.0001) was found between histological subtype and CK7/CK20 immunostaining profile. The 5-year survival rate varied from 100% for CK7-/CK20 + AC to 40% for CK7 + /CK20- AC. CONCLUSION: In our study, the intestinal histological subtype had a favorable prognostic value. CK7/CK20 immunostaining profile was helpful for the identification of histological subtype and appears to provide additional prognostic information.

Characterization of an adaptive immune response in microsatellite-instable colorectal cancer.

Sporadic or hereditary colorectal cancer (CRC) with microsatellite instability (MSI) is frequently characterized by inflammatory lymphocytic infiltration and tends to be associated with a better outcome than microsatellite stable (MSS) CRC, probably reflecting a more effective immune response. We investigated inflammatory mechanisms in 48 MSI CRCs and 62 MSS CRCs by analyzing: (1) the expression of 48 cytokines using Bio-Plex multiplex cytokine assays, and (2) the in situ immune response by immunohistochemical analysis with antibodies against CD3 (T lymphocytes), CD8 (cytotoxic T lymphocytes), CD45RO (memory T lymphocytes), T-bet (Th1 CD4 cells), and FoxP3 (regulatory T cells). MSI CRC exhibited significantly higher expression of CCL5 (RANTES), CXCL8 (IL-8), CXCL9 (MIG), IL-1ß, CXCL10 (IP-10), IL-16, CXCL1 (GROα), and IL-1ra, and lower expression of MIF, compared with MSS CRC. Immunohistochemistry combined with image analysis indicated that the density of CD3+, CD8+, CD45RO+, and T-bet+ T lymphocytes was higher in MSI CRC than in MSS CRC, whereas the number of regulatory T cells (FoxP3+) was not statistically different between the groups. These results indicate that MSI CRC is associated with a specific cytokine expression profile that includes CCL5, CXCL10, and CXCL9, which are involved in the T helper type 1 (Th1) response and in the recruitment of memory CD45RO+ T cells. Our findings highlight the major role of adaptive immunity in MSI CRC and provide a possible explanation for the more favorable prognosis of this CRC subtype.