Our data suggest that the tumour or peri-tumoural microenvironment may act to modify the observed pattern of immune response. Immune cell infiltration and the presence of concurrent CLT helped characterize specific tumour histotypes associated with favourable prognostic features.

No abstract

B7H1 is consistently associated with inhibition of the immune system in many solid tumors. However, there is no report about its impact on differentiated thyroid carcinoma (DTC) presentation, aggressiveness, or evolution. Aiming to investigate the role of B7H1 in DTC and correlate this protein with other tumor-infiltrating immune cells, we studied 407 thyroid nodule tissue samples including 293 from DTC patients, all managed according to a same standard protocol. In addition, we obtained 5 normal and 114 benign thyroid lesions. Eighteen out of the 253 papillary thyroid carcinomas were paired with respective metastatic lymph node tissues. B7H1 (CD274) protein expression was assessed by immunohistochemistry and the gene expression was quantified by real-time PCR. Malignant tissues displayed a more intense B7H1 staining and higher mRNA levels than benign tissues (both P!0.0001). We observed a positive linear correlation between higher age at diagnosis and B7H1 mRNA levels (PZ0.02896). Elevated levels of B7H1 protein were associated with the presence of CD4C, CD8C, CD20C, and FoxP3C lymphocytes (all P!0.05); tumor-associated macrophages (P!0.0001); and the presence of myeloid-derived suppressor cells (PZ0.03256). Stage II-IV patients presented higher B7H1 mRNA levels than stage I cases (PZ0.03522). On the contrary, a decreased expression of B7H1 protein was observed in lymph node metastasis (PZ0.0152). In conclusion, our data demonstrate that B7H1 expression is associated with features of aggressiveness, suggesting that this is an immune evasion mechanism of DTC cells.

In contrast to most human malignancies, epidemiologic studies have frequently reported a reduced risk of differentiated thyroid cancer in tobacco consumers. Cytochrome P4501A1 (CYP1A1) gene variants may be related to an increased capacity to activate polycyclic aromatic hydrocarbons, producing highly reactive electrophilic intermediates that might damage DNA. Hence, the germline inheritance of a wild-type CYP1A1 gene may decrease the susceptibility for thyroid cancer. The present study was designed to investigate CYP1A1 (m1 and m2) role in thyroid tumorigenesis and its connection with GSTM1, GSTT1, GSTP1, GSTO1, and codon 72 of p53 genotypes. A total of 248 patients with thyroid nodules, including 67 benign goiters, 13 follicular adenomas, 136 papillary carcinomas, and 32 follicular carcinomas, and 277 controls with similar ethnic backgrounds were interviewed on their lifetime dietary and occupational histories, smoking habit, previous diseases, and other anamnestic data. DNA was extracted from a blood sample and submitted to PCR-restriction fragment length polymorphism assays. The wild-type CYP1A1m1 genotype was more frequent among papillary carcinoma patients (74.26%) than in the control population (62.45%; PZ0.0147), reducing the risk for this type of cancer (odds ratioZ 0.564; 95% confidence intervalZ0.357-0.894). A multiple logistic regression analysis showed an inverse correlation between cigarette smoking (PZ0.0385) and CYP1A1 germline inheritance (PZ0.0237) with the susceptibility to papillary carcinomas. We were not able to find any correlation between smoking, clinical features, parameters of aggressiveness at diagnosis or during follow-up, and any of the GST or CYP genotypes considered separately or in different combinations. We suggest that CYP1A1 genotype might be associated with the reported reduced risk to papillary carcinomas among smokers.

In conclusion, we suggest the use of a relatively simple pathology tool to help select cases that may benefit of a more aggressive approach sparing the majority of patients from unnecessary procedures.