ABSTRACT
Background and objectives: In patients with colorectal cancer (CRC), heterogeneous expression of Mismatch repair (MMR) proteins can manifest itself in several different forms and is not such a rare phenomenon. Therefore, it is very important to recognize the nuclear expression of MMR proteins of different MMR status in order to avoid false positive or false negative results. The aim of this study was to determine the frequency and distribution of heterogeneous expression of MMR proteins in patients with stages II and III of the disease as well as its association with clinical, demographic and pathological characteristics of CRC in relation to proficient and deficient expression of MMR proteins. Material and Methods: The study included 104 cases of colorectal cancer obtained from surgical colectomy material in stages II and III of the disease. Results: From a total of 104 patients with colorectal cancer, immunohistochemical analysis of the expression of all four MMR proteins showed that heterogeneous expression of MMR proteins (as well as deficient immunoreactivity of tumor cells) was present in 12 cases, while proficient expression of MMR proteins was detected in 80 tumors. Conclusions: Our study showed that the only independent predictors of the loss of MMR protein expression were younger patient age and right-sided anatomical location of the tumor. The study also established the existence of heterogeneous expression of MMR proteins in a non-negligible percentage of CRCs (11.5%), where heterogeneous nuclear expression of MMR proteins was described in several different forms.
Subject(s)
Colorectal Neoplasms , Humans , Colorectal Neoplasms/pathology , Neoplasm Staging , Adaptor Proteins, Signal Transducing , MutL Protein Homolog 1/metabolismABSTRACT
Background and objectives: Deficient mismatch repair (MMR) status is associated with good prognosis but poor therapeutic response to adjuvant chemotherapy in patients with colorectal cancer. However, there are some opposed arguments considering therapeutic outcomes in patients with evidenced MMR deficiency in colorectal cancer. The aim of the study was the investigation of prognostic value and immunohistochemical analysis of the MMR-deficiency tumors. Materials and Methods: The study enrolled 104 patients with resected stage II and III colorectal cancer samples from the period 2018-2019. Results: The tumors with deficient MMR status were significantly associated with age up to 50 years and right-sided localization (p < 0.001). During the follow-up period of 22.43 ± 6.66 months, 21 patients (20.2%) died, whereas 14 patients (13.5%) had relapses. The loss of mutL homologue 1/postmeiotic segregation increased 2 (MLH1/PMS2) expression, compared to proficient MMR tumors, was associated with shorter disease-free survival in patients with lymphovascular invasion (p < 0.05), perineural invasion (p < 0.01), stage III (p < 0.05) and high-grade tumor (p < 0.05). Conclusions: This retrospective pilot study of a single-center cohort of patients with stage II and III colorectal cancer highlights the clinical importance of using immunohistochemistry (IHC) analysis as a guide for diagnostic algorithm in a country with limited resources, but with a high prevalence of colorectal carcinoma in the young patients. MMR-deficiency tumors compared with proficient MMR colorectal cancer was not shown to be a significant predictor of disease-free and overall survival.
Subject(s)
Colorectal Neoplasms , Neoplasm Recurrence, Local , Brain Neoplasms , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Humans , MutL Protein Homolog 1/genetics , Neoplasm Staging , Neoplastic Syndromes, Hereditary , Pilot Projects , Prognosis , Retrospective StudiesABSTRACT
This paper is dedicated to the description of superheating as a method for antigen retrieval. In our investigation, this antigen retrieval method was used on thermal plate, heating tissue sections at temperature 120° C for 90 minutes. In the research we conducted the superheating method was applied to formalin-fixed paraffin-embedded tissue sections of breast tumors. The following monoclonal antibodies were used: estrogen receptor, progesterone receptor, epithelial membrane antigen, CD34, and Ki-67. With these tested antibodies we had good staining and no loss of tissue sections during the staining process.
