Plasma levels of progranulin, a tumorigenic protein, are persistently elevated during the first month after minimally invasive colorectal cancer resection

Background: Progranulin (PGRN), also identified as Precursor cell-derived growth factor (PCDGF), is a glycoprotein that is expressed and released ubiquitously. PGRN is plays a crucial role in regulating cell proliferation, differentiation, and pathological pathways. PGRN overexpression has been noted in many cancers and plays an important role in wound healing. Surgery's impact on PGRN levels is unknown. The aim of this study was to assess the levels of plasma PGRN before during the first month after minimally invasive colorectal resection (MICR) for colorectal cancer (CRC) resection.

Methods: CRC patients who were enrolled in a data/plasma bank approved by an Institutional Review Board and underwent MICR for whom adequate plasma samples were available were studied. Blood samples were obtained before surgery and at different time intervals after the operation and late samples were grouped into 7-day blocks and considered as single time points. PGRN levels (pg/mL) were determined in duplicate via ELISA and reported as median and 95% confidence interval (95% CI) values. The paired t-test was used for statistical analysis.

Results: Preoperative and 1 or more late postoperative plasma sample were available for 93 MICR CRC patients. The distribution of cancer stages in the final analysis was: stage I accounted for 37% of cases, stage II for 27%, stage III for 32%, and stage IV for 4%. The median preoperative PGRN level was 50.69 pg/mL, 95% CI: 47.71-56.30, n=93. When compared to preoperative levels, significantly elevated (P<0.001) median levels (pg/mL) were noted on postoperative day (POD) 1 (64.78, 95% CI: 60.86-68.83, n=92), POD 3 (69.15, 95% CI: 66.43-74.32, n=85), POD 7-13 (63.93, 95% CI: 59.62-68.35, n=68), and POD 14-20 (68.19, 95% CI: 60.12-73.37, n=26), POD 21-27 (67.38, 95% CI: 60.30-76.65, n=20) and on POD 28-41 (75.13, 95% CI: 54.02-83.16, n=22; P<0.01).

Conclusions: Following surgery for CRC, plasma PGRN levels showed a significant increase compared to baseline levels, persisting for a duration of one month. This initial surge post-operation could potentially be attributed to the transient acute inflammatory response. The elevation observed in weeks 2 and 4 could potentially be attributed to the process of wound healing, as PGRN has been shown to enhance the accumulation of fibroblasts and facilitate angiogenesis within wounds. Additional investigation is warranted.