Examination of p16, p21, p53 and p57 expression in other patients with benign diagnosis and prostate adenocarcinoma in transuretral resection materials

Prostate cancer is the 2nd most common cancer in men in the world, and it ranks 5th among cancers that cause death. The prevalence of prostate cancer in men aged 80 years and older can reach % 59. Prostate specific antigen (PSA) is a serum marker used in the diagnosis of prostate cancer. PSA values are a test used in follow-up to detect recurrence or metastasis in patients diagnosed with prostate cancer. The prostate gland consists of two parts, inner (transitional zone) and outer (peripheral and central zone). Prostate cancer mostly originates from the outer part. It is known that mostly benign prostatic hyperplasia (BPH) develops in the inner part. With transurethral resection (TUR), sampling is made from the inner part of the prostate gland, where BPH is more common. The diagnosis of prostate cancer in TUR materials is actually an unexpected situation. TUR; It is not a diagnostic procedure in cases where tumor is considered. Transrectal ultrasonography guided prostate biopsy (TRUS) is preferred for this and the treatment is planned accordingly. TUR is a procedure to improve urethral symptoms in BPH cases and rare cases of tumors that do not respond to treatment. Therefore, most of the prostate cancer cases in our study were found by chance. In our study, it was aimed to examine the staining pattern of cell cycle inhibitors p16, p21, p53 and p57 with the immunohistochemical (IHC) method in prostate adenocarcinoma (PCa) and other cases with benign diagnosis in TUR materials, to compare the findings, to evaluate the results and to shed light on these and similar studies. Material and Method: All cases diagnosed as PCa in TUR materials at Recep Tayyip Erdogan University Faculty of Medicine between 2014 and 2021 were included in the study. The other group was randomly selected from cases diagnosed with nodular hyperplasia or BPH in TUR materials. Blocks were removed from the pathology archive and new blocks were created using the tissue microarray (TMA) method. After 3 mm cores were extracted and mapped from the blocks with the TMA method, new blocks were planted. A total of 2 cores were taken from each case with PCa, one core from the cancer area and one core from the benign area around cancer. In the other group, one core was taken from each of the BPH cases. Because some of the PCa cases were all tumors or had no benign areas, these cases were not vii included in the statistical analysis. As a result, a total of 219 cases, 107 cases in the cancer group and 112 cases in the benign group, were included in our study. IHC panel consisting of p16 (anti-p16INK4a-E6H4), p21 WAF1/CIP1 (DCS-60.2), p53 (Bp53-11) and p57/Kip2 (Kp 10) was applied to each of the blocks created. Statistical significance was investigated by comparing the staining status in the surrounding benign areas and BPH cases, and the results were analyzed with the Pearson chi-square method. Results with a statistical significance value of p<0.05 were considered significant. Results: The mean age of the cases in the cancer group was 75.4, and it was calculated as 68.9 in the BPH group. The mean total PSA value was 58.9 in the cancer group and 5.2 in the BPH group. The most common patterns in the cancer group; pattern 3 was found in 45 cases (42%), pattern 4 in 47 cases (44%), and pattern 5 in 15 cases (14%). The most common patterns in the cancer group; Pattern 3 was found in 45 cases (42%), pattern 4 in 47 cases (44%), and pattern 5 in 15 cases (14%). Perineural invasion was observed in 27 (25%) of the cases, necrosis in 2 (2%) and angiolymphatic invasion in 6 (6%) cases. IHC staining results were compared in 3 groups: cancer group, benign areas around cancer and BPH group. Accordingly, p16 and p21 were stained higher in cancer areas compared to benign areas around cancer and BPH cases (p<0.001). Mutational staining with p53 was more common in cancer areas (p<0.001). There was no significant relationship between p57 and the groups (p=0.386). There was no significant relationship between p57 and the groups (p=0.386). In addition, mutational staining with p53 was observed more in BPH cases (p=0.017). However, there was no significant relationship between the groups with p21 and p57 (p=0.765, p=1). In the cancer group, group 2 and group 3 cases with a combined score of 7 were combined into a single group due to the insufficient number of cases. Group 4 cases were not included in the statistical analysis due to the small number of cases. Thus, IHC staining status was examined in 3 groups: grade group 1, group 2+3 and group 5. In the cancer group, p16, p21 and p57 expression were increased in grade group 5 cases compared to group 1 cases (p<0.001, p=0.007, p<0.001). There was no significant relationship between p53 and the groups (p=0.203). In group 2+3 cases, p16 expression was higher than in group 1 cases (p=0.001). However, mutational staining with p53 was more common in group 1 cases than viii with group 2+3 (p=0.034). There was no statistically significant difference between the groups with p21 and p57 (p=0.203, p=1). In group 5 cases, p57 expression was increased compared to group 2+3 cases (p<0.001). However, there was no significant difference between the groups with p16, p21 and p53 (p=0.321, p=0.157, p=0.395). Conclusion: In TUR materials, p16, p21 expression is increased in PCa areas compared to benign areas around cancer and BPH cases, and mutational staining with p53 is more common. Since there was no significant difference between p57 and the groups, the cancer-inhibiting effect of p57 could not be demonstrated by IHC. Although it is less than cancer areas, p16 and p21 stained in benign areas around cancer. Therefore, no cancer-specific staining with p16 and p21 was observed in PCa cases in TUR materials. In BPH cases, p16 expression was higher than in benign areas around cancer, and the number of cases with mutational negative staining with p53 was found to be higher. It is thought that the reason for this IHC staining, which is unexpectedly seen in BPH cases, may be due to the effect of Human Papilloma Virus (HPV). It was investigated whether p21 and p53 correlated expression as IHC in PCa. Accordingly, there are findings consistent with the correlation as IHC in BPH cases and benign areas around PCa. There are findings consistent with the p21 correlation in the wild-type staining of p53 in cancer areas, but no correlation was observed between p53 mutational staining and p21. Therefore, it was thought that there is a p53-independent pathway that stimulates p21 in PCa cases with mutational staining with p53 in TUR materials. p16 showed higher expression in intermediate and undifferentiated cancers than in well-differentiated cancers. Because p16 stains with high intensity in high-grade tumors, it is thought that it may be an alternative IHC stain to AMACR in the diagnosis of high-grade PCa. However, no difference in p16 staining was found between intermediate and undifferentiated cancers. There is a difference in staining between p21 and only undifferentiated cancers and well-differentiated cancers. p21 stained higher in undifferentiated cancers. Although most of the p53 mutant positive cases were high grade, statistically significant results could not be obtained. The reason for this is that negative staining with p53 is considered as mutational staining and p53 negativity is mostly seen in grade group 1 tumors in our study. Therefore, there was no statistically significant difference ix with p53 between undifferentiated cancers and well and moderately differentiated cancers. In well-differentiated cancers, p53 mutational staining was more common than in moderately differentiated tumors. Therefore, in our study, the relationship between p53 mutational staining and high grade tumor could not be shown statistically in PCa cases. p57 expression was found to be higher in undifferentiated cancers compared to well and moderately differentiated cancers. Therefore, the suppressive role of p57 in cancer in PCa cases in TUR materials could not be supported as IHC. On the contrary, its higher staining suggested that p57 is stimulated by a different mechanism in undifferentiated PCa. More work is needed in this respect. Cases with moderate and above positive staining with p16 and negative staining with p53 in PCa may be associated with HPV. However, it could not be confirmed due to the need for molecular testing. Keywords: Prostate cancer, p16, p21, p53, p57