ObjectiveTo explore the expressions of P27Kip1, RalA, and SPOCK1 in cancer tissues of the elderly patients with colorectal cancer (CRC) and the relations between their expressions and clinical pathological characteristics as well as prognosis. MethodsThe clinicopathologic data of elderly CRC patients treated and underwent surgical resection in Kailuan General Hospital Linxi Hospital from May 2019 to May 2022 were collected in a retrospective manner. The immunohistochemistry was used to detect the expressions of P27Kip1, RalA, and SPOCK1 proteins in the CRC tissues and corresponding adjacent tissues. The Kaplan-Meier method was applied to analyze the survival of CRC patients with p27Kip1, RalA, and SPOCK1 positive and negative expressions. The multivariate Cox risk regression model was applied to analyze the influencing factors of prognosis in the patients with CRC. The test level was set as α=0.05. ResultsA total of 149 elderly CRC patients were enrolled. All patients were followed up for 2 years, and 45 cases died of cancer during the follow-up period. The positive rate of p27Kip1 protein expression in the CRC tissues was lower than that in the corresponding adjacent tissues (P<0.05), while the positive rates of RalA and SPOCK1 protein expressions were higher than those in the corresponding adjacent tissues (P<0.05). The proportions of mucinous carcinoma, TNM stages Ⅲ–Ⅳ, low differentiation, positive lymph node metastasis, and T staging T2–T4 in the patients with negative p27Kip1 and positive RalA and SPOCK1 expressions were higher than those in the patients with positive p27Kip1 and negative RalA and SPOCK1 expressions (P<0.05). The proportions of patients with TNM stages Ⅲ–Ⅳ, negative p27Kip1 and positive RalA and SPOCK1 expressions in the death group were higher than that in the survival group (P<0.05). The survival curves plotted by the Kaplan-Meier method showed that the survival curves of patients with positive expression of p27Kip1 and negative expression of RalA and SPOCK1 in the cancer tissues were significantly better than those with negative expression of p27Kip1 and positive expression of RalA and SPOCK1 (respectively: log-rank χ²=11.678, P=0.001; log-rank χ²=10.836, P=0.001; log-rank χ²=10.792, P=0.001). The multivariate Cox proportional hazards regression model analysis revealed that the negative expression of p27Kip1 [HR(95%CI)=2.807(1.490, 5.287)], positive expression of RalA [HR(95%CI)=2.769(1.493, 5.134)], and positive expression of SPOCK1 [HR(95%CI)=3.075(1.610, 5.871)] were independent risk factors for postoperative mortality in CRC patients. ConclusionThe results of this study suggest that the positive rate of p27Kip1 protein expression is low in CRC tissues, while the positive rates of RalaA and SPOCK1 protein expression are high, and the protein expression of these three indicators are associated with tissue type, TNM stage, degree of differentiation, lymph node metastasis, and T stage. Negative expression of p27Kip1 and positive expression of RalA and SPOCK1 are unfavorable for the prognosis of CRC patients.