A pleiotropy scan to discover new susceptibility loci for pancreatic ductal adenocarcinoma.

Pleiotropic variants (i.e., genetic polymorphisms influencing more than one phenotype) are often associated with cancer risk. A scan of pleiotropic variants was successfully conducted ten years ago in relation to pancreatic ductal adenocarcinoma susceptibility. However, in the last decade, genetic association studies performed on several human traits have greatly increased the number of known pleiotropic variants. Based on the hypothesis that variants already associated with a least one trait have a higher probability of association with other traits, 61,052 variants reported to be associated by at least one genome wide association study (GWAS) with at least one human trait were tested in the present study consisting of two phases (discovery and validation), comprising a total of 16,055 pancreatic ductal adenocarcinoma (PDAC) cases and 212,149 controls. The meta-analysis of the two phases showed two loci (10q21.1-rs4948550 (P=6.52×10-5) and 7q36.3-rs288762 (P=3.03×10-5) potentially associated with PDAC risk. 10q21.1-rs4948550 shows a high degree of pleiotropy and it is also associated with colorectal cancer risk while 7q36.3-rs288762 is situated 28,558 base pairs upstream of the Sonic Hedgehog (SHH) gene, which is involved in the cell differentiation process and PDAC etiopathogenesis. In conclusion, none of the single nucleotide polymorphisms (SNPs) showed a formally statistically significant association after correction for multiple testing. However, given their pleiotropic nature and association with various human traits including colorectal cancer, the two SNPs showing the best associations with PDAC risk merit further investigation through fine mapping and ad hoc functional studies.

Gender-related differences in patients with carcinoid syndrome: new insights from an Italian multicenter cohort study.

BACKGROUND: The incidence of neuroendocrine neoplasm (NEN) and related carcinoid syndrome (CaS) has increased markedly in recent decades, and women appear to be more at risk than men. As per other tumors, gender may be relevant in influencing the clinical and prognostic characteristics of NEN-associated CS. However, specific data on carcinoid syndrome (CaS) are still lacking. PURPOSE: To evaluate gender differences in clinical presentation and outcome of CaS. METHODS: Retrospective analysis of 144 CaS patients from 20 Italian high-volume centers was conducted. Clinical presentation, tumor characteristics, therapies, and outcomes (progression-free survival, PFS, overall survival, OS) were correlated to gender. RESULTS: Ninety (62.5%) CaS patients were male. There was no gender difference in the site of primary tumor, tumor grade and clinical stage, as well as in treatments. Men were more frequently smokers (37.2%) and alcohol drinkers (17.8%) than women (9.5%, p = 0.002, and 3.7%, p = 0.004, respectively). Concerning clinical presentation, women showed higher median number of symptoms (p = 0.0007), more frequent abdominal pain, tachycardia, and psychiatric disorders than men (53.3% vs 70.4%, p = 0.044; 6.7% vs 31.5%, p = 0.001; 50.9% vs. 26.7%, p = 0.003, respectively). Lymph node metastases at diagnosis were more frequent in men than in women (80% vs 64.8%; p = 0.04), but no differences in terms of PFS (p = 0.51) and OS (p = 0.64) were found between gender. CONCLUSIONS: In this Italian cohort, CaS was slightly more frequent in males than females. Gender-related differences emerged in the clinical presentation of CaS, as well as gender-specific risk factors for CaS development. A gender-driven clinical management of these patients should be advisable.

Radical Resection in Entero-Pancreatic Neuroendocrine Tumors: Recurrence-Free Survival Rate and Definition of a Risk Score for Recurrence.

BACKGROUND: Surgery with radical intent is the only potentially curative option for entero-pancreatic neuroendocrine tumors (EP-NETs) but many patients develop recurrence even after many years. The subset of patients at high risk of disease recurrence has not been clearly defined to date. OBJECTIVE: The aim of this retrospective study was to define, in a series of completely resected EP-NETs, the recurrence-free survival (RFS) rate and a risk score for disease recurrence. PATIENTS AND METHODS: This was a multicenter retrospective analysis of sporadic pancreatic NETs (PanNETs) or small intestine NETs (SiNETs) [G1/G2] that underwent R0/R1 surgery (years 2000-2016) with at least a 24-month follow-up. Survival analysis was performed using the Kaplan-Meier method and risk factor analysis was performed using the Cox regression model. RESULTS: Overall, 441 patients (224 PanNETs and 217 SiNETs) were included, with a median Ki67 of 2% in tumor tissue and 8.2% stage IV disease. Median RFS was 101 months (5-year rate 67.9%). The derived prognostic score defined by multivariable analysis included prognostic parameters, such as TNM stage, lymph node ratio, margin status, and grading. The score distinguished three risk categories with a significantly different RFS (p < 0.01). CONCLUSIONS: Approximately 30% of patients with EP-NETs recurred within 5 years after radical surgery. Risk factors for recurrence were disease stage, lymph node ratio, margin status, and grading. The definition of risk categories may help in selecting patients who might benefit from adjuvant treatments and more intensive follow-up programs.

Long-term outcomes after pancreatoduodenectomy for ampullary cancer: The influence of the histological subtypes and comparison with the other periampullary neoplasms.

BACKGROUND: Ampullary carcinoma (AC) is histologically classified as intestinal (In-AC), pancreaticobiliary (Pb-AC) or mixed-AC. The prognostic role of AC subtypes has been debated and remains unclear. The aims of this study were to evaluate outcomes after pancreatoduodenectomy (PD) for each subtype of AC and to compare these with pancreatic ductal adenocarcinoma [PDAC] and distal cholangiocarcinoma [DCC]. METHODS: PDs performed for AC between 2010 and 2018 were retrospectively evaluated. Histological subtype was obtained for all patients. One-year, 3-year and 5-year disease-free-survival (DFS) and overall survival (OS) rates were calculated. Kaplan-Meier survival analysis was performed to compare Pb-AC, In-AC and mixed-AC. Comparison with PDs performed for PDAC and DCC during the same period was also performed. RESULTS: A total of 97 patients undergoing PD for AC were evaluated: 34 (35.1%) In-AC, 54 (55.7%) Pb-AC and 9 mixed-AC (9.3%). DFS and OS rates for Pb-AC were significantly lower compared to In-AC (p < 0.05 and p < 0.01), but similar to mixed-AC (p = 0.3 and p = 0.4). Adjuvant therapy was not associated with increased survival, regardless of the histological subtype (p > 0.05). During the same period, 337 and 53 PDs for PDAC and DCC, respectively, were performed. In-AC was associated with significantly better outcomes compared to PDAC and DCC (p < 0.001); DFS and OS rates for Pb-AC and mixed AC were significantly higher compared to PDAC (p < 0.001), but similar to DCC (p > 0.05). CONCLUSIONS: Pb-AC has significantly worse survival compared to In-AC. Moreover, mixed-AC should be considered as Pb-AC. Pb-AC and mixed-AC seem to have better prognosis compared to PDAC, but similar to DCC.

Risk of preoperative understaging of duodenal neuroendocrine neoplasms: a plea for caution in the treatment strategy.

PURPOSE: Pretreatment staging is the milestone for planning either surgical or endoscopic treatment in duodenal neuroendocrine neoplasms (dNENs). Herein, a series of surgically treated dNEN patients was evaluated to assess the concordance between the pre- and postsurgical staging. METHODS: Retrospective analysis of patients with a histologically confirmed diagnosis of dNENs, who underwent surgical resection observed at eight Italian tertiary referral centers. The presurgical TNM stage, based on the radiological and functional imaging, was compared with the pathological TNM stage, after surgery. RESULTS: From 2000 to 2019, 109 patients were included. Sixty-six patients had G1, 26 a G2, 7 a G3 dNEN (Ki-67 not available in 10 patients). In 46/109 patients (42%) there was disagreement between the pre- and postsurgical staging, being it understaged in 42 patients (38%), overstaged in 4 (3%). As regards understaging, in 25 patients (22.9%), metastatic loco-regional nodes (N) resulted undetected at both radiological and functional imaging. Understaging due to the presence of distal micrometastases (M) was observed in 2 cases (1.8%). Underestimation of tumor extent (T) was observed in 12 patients (11%); in three cases the tumor was understaged both in T and N extent. CONCLUSIONS: Conventional imaging has a poor detection rate for loco-regional nodes and micrometastases in the presurgical setting of the dNENs. These results represent important advice when local conservative approaches, such as endoscopy or local surgical excision are considered and it represents a strong recommendation to include endoscopic ultrasound in the preoperative tools for a more accurate local staging.

Immune infiltrating cells in duodenal cancers.

BACKGROUND: Duodenal adenocarcinoma (DA) is a rare yet aggressive malignancy, with increasing incidence in the last decades. Its low frequency has hampered a thorough understanding of the pathogenesis of the disease and of its biology, limiting the identification of tailored therapeutic options. A large body of evidence has clearly shown the clinical relevance of immune cells in solid tumors, correlating immune features with post-surgical prognosis. The aim of this study was to analyze the immune contexture in a cohort of duodenal adenocarcinomas surgically resected at our Institution and define its correlation with clinical variables. METHODS: Tissue slides from paraffin-embedded tumor specimens of 15 consecutive DA and 3 adenomas that underwent a pancreaticoduodenectomy in our center between 2010 to 2018 were immunohistochemically stained. The density (percentage of immune reactive area, IRA%) of immune markers CD45RO, CD8, CD20, IL-17, PD-1, CD68 was quantified by computer-assisted image analysis. Demographic, clinical, histopathological data were collected. RESULTS: In our population, median IRA % (IQR) of immune subsets was respectively CD45RO-TILs 2.19 (2.14), CD8-TIL 0.42 (0.81), CD20-TILs 0.22 (0.51), CD20-TLT 2.84 (4.64), CD68-TAM 2.19 (1.56), IL17+ cells 0.39 (0.39), PD1-TILs 0.19 (0.41). The median follow-up was 47.5 (22.4-63.3) months. At statistical analysis, the density of CD8-TILs inversely correlated with lymph node ratio (p = 0.013), number of metastatic lymph nodes (p = 0.019), and was lower in N+ adenocarcinomas compared to N0 (1.07 vs 0.29; p = 0.093), albeit not significantly. Stratifying patients for the N status, the density of CD8-TILs decreased with the increasing of the N stage (p = 0.065) and was lower in patients who experienced recurrence and died for the disease (0.276 vs 0.641; p = 0.044). Notably, also CD68-TAM distribution was different in patients who had recurrence versus patients who did not (1.028 vs 2.276; p = 0.036). CONCLUSIONS: Immune cells showed variable expression in correlation with common prognostic factors, suggesting T cell infiltration may play a protective role towards lymphatic spread of disease and nodal metastatization. Furthermore, T cell density and macrophage infiltration were associated to a lower risk of recurrence and disease related death. A multicentric approach may be indicated to allow analysis of larger cohorts of patients, potentially increasing the power of our observations.

Minimally Invasive Pancreatic Resection: Is It Really the Future?

The introduction and widespread application of minimally invasive surgery has been one of the most important innovations that radically changed the practice of surgery during the last few decades. The application to pancreatic surgery of minimally invasive approach has only recently emerged: both laparoscopic distal pancreatectomy (LDP) and laparoscopic pancreaticoduodenectomy (LPD) can be competently performed. LDP and LPD are advocated to improved perioperative outcomes, including decreased blood loss, shorter length of stay, reduced postoperative pain and expedited time to functional recovery. However, the indication to minimally invasive approach for pancreatic surgery is often benign or low-grade malignant pathologies. In this review, we summarize the current data on minimally invasive pancreatic surgery, focusing on indication, perioperative and oncological outcomes.

Locally advanced pancreatic duct adenocarcinoma: pancreatectomy with planned arterial resection based on axial arterial encasement.

Pancreatectomy with arterial resection for locally advanced pancreatic duct adenocarcinoma (PDA) is associated with high morbidity and is thus considered as a contraindication. The aim of our study was to report our experience of pancreatectomy with planned arterial resection for locally advanced PDA based on specific selection criteria. MATERIAL AND METHODS: All patients receiving pancreatectomy for PDA between October 2008 and July 2014 were reviewed. The patients were classified into group 1, pancreatectomy without vascular resection (66 patients); group 2, pancreatectomy with isolated venous resection (31 patients), and group 3, pancreatectomy with arterial resection for locally advanced PDA (14 patients). The primary selection criteria for arterial resection was the possibility of achieving a complete resection based on the extent of axial encasement, the absence of tumor invasion at the origin of celiac trunk (CT) and superior mesenteric artery (SMA), and a free distal arterial segment allowing reconstruction. Patient outcomes and survival were analyzed. RESULTS: Six SMA, two CT, four common hepatic artery, and two replaced right hepatic artery resections were undertaken. The preferred arterial reconstruction was splenic artery transposition. Group 3 had a higher preoperative weight loss, a longer operative time, and a higher incidence of intraoperative blood transfusion. Ninety-day mortality occurred in three patients in groups 1 and 2. There were no statistically significant differences in the incidence, grade, and type of complications in the three groups. Postoperative pancreatic fistula and postpancreatectomy hemorrhage were also comparable. In group 3, none had arterial wall invasion and nine patients had recurrence (seven metastatic and two loco-regional). Survival and disease-free survival were comparable between groups. CONCLUSION: Planned arterial resection for PDA can be performed safely with a good outcome in highly selected patients. Key elements for defining the resectability is based on the extent of the axial arterial encasement with two criteria: the origin of the CT and SMA are free from tumor invasion and the possibility of distal reconstruction.

hERG1 channels drive tumour malignancy and may serve as prognostic factor in pancreatic ductal adenocarcinoma.

BACKGROUND: hERG1 channels are aberrantly expressed in human cancers. The expression, functional role and clinical significance of hERG1 channels in pancreatic ductal adenocarcinoma (PDAC) is lacking. METHODS: hERG1 expression was tested in PDAC primary samples assembled as tissue microarray by immunohistochemistry using an anti-hERG1 monoclonal antibody (α-hERG1-MoAb). The functional role of hERG1 was studied in PDAC cell lines and primary cultures. ERG1 expression during PDAC progression was studied in Pdx-1-Cre,LSL-Kras(G12D/+),LSL-Trp53(R175H/+) transgenic (KPC) mice. ERG1 expression in vivo was determined by optical imaging using Alexa-680-labelled α-hERG1-MoAb. RESULTS: (i) hERG1 was expressed at high levels in 59% of primary PDAC; (ii) hERG1 blockade decreased PDAC cell growth and migration; (iii) hERG1 was physically and functionally linked to the Epidermal Growth Factor-Receptor pathway; (iv) in transgenic mice, ERG1 was expressed in PanIN lesions, reaching high expression levels in PDAC; (v) PDAC patients whose primary tumour showed high hERG1 expression had a worse prognosis; (vi) the α-hERG1-MoAb could detect PDAC in vivo. CONCLUSIONS: hERG1 regulates PDAC malignancy and its expression, once validated in a larger cohort also comprising of late-stage, non-surgically resected cases, may be exploited for diagnostic and prognostic purposes in PDAC either ex vivo or in vivo.

Complete pathological response after FOLFIRINOX for locally advanced pancreatic cancer. The beginning of a new era? Case report and review of the literature.

Neoadjuvant treatments (chemo or chemoradiation therapy) are used for patients with locally advanced Pancreatic Ductal Adeno-Carcinoma (PDAC). FOLFIRINOX is now considered an effective treatment modality for patients with metastatic pancreatic cancer and a promising option for patients with locally advanced PDAC. Complete pathologic response after neoadjuvant therapies is anecdotic and its prognostic impact is completely unclear. We report the case of a complete pathological response after treatment with FOLFIRINOX in a patient affected by a locally advanced PDAC with a review of the literature regarding the use of FOLFIRINOX for locally advanced PDAC.

Pathologic tumor response to neoadjuvant therapy in resected pancreatic cancer: does it affect prognosis?

Neoadjuvant therapy (NAT) + surgical resection for pancreatic cancer (PC) has gained consensus in recent years. Pathological response (PR) is generally assessed according to the College of American Pathologists grading system, ranging from 0 (complete response) to 3 (no response). The aim of our study is to evaluate the PR in a series of resections for PC after NAT and its prognostic implication. 112 patients undergone NAT and resection for PC between 2011 and 2020 were retrospectively evaluated. PR was 0/1, 2 and 3 in 18 (15%), 79 (61%) and 29 (24%) cases, respectively. Chemotherapy regimens different from FOLFIRINOX and gemcitabine + nab-paclitaxel (OR 11.61 (2.53-53.36), p = 0.002) and lymphovascular invasion (OR 11.28 (1.89-67.23), p = 0.008) were associated to PR-3. Median follow-up was 25.8 (3.6-130.5) months. For PR-0/1, PR-2 and PR-3, median DFS was 45.8, 11.5, 4.6 months (p < 0.0001), respectively, while median OS was not reached, 27.1 and 17.5 months (p = 0.0006), respectively. At univariate analysis, PR-0/1 was significantly associated to better DFS and OS (HR 0.33 (0.17-0.67), p = 0.002; HR 0.20 (0.07-0.54), p = 0.002, respectively). At multivariate analysis, pancreaticoduodenectomy (HR 0.50 (0.30-0.84), p = 0.009), LNR (HR 27.14 (1.21-608.9), p = 0.038) and lymphovascular invasion (HR 1.99 (1.06-3.76), p = 0.033) were independently associated to DFS; pre-treatment CA 19.9 value (HR 1.00 (1.00-1.00), p = 0.025), post-treatment resectability status (HR 0.51 (0.28-0.95), p = 0.035), pancreaticoduodenectomy (HR 0.56 (0.32-0.99), p = 0.050), severe morbidity (2.99 (1.22-7.55), p = 0.017), LNR (HR 56.8 (2.08-1548.3), p = 0.017), lymphovascular invasion (HR 2.18 (1.08-4.37), p = 0.029) were independently associated to OS. PR did not reach statistical significance at multivariate analysis. A favorable PR is observed only in a limited number of cases. The prognostic role of PR, despite being promising, remains unclear and further multicentric studies are needed.

The Number of Metastatic Lymph Nodes is a Useful Predictive Factor for Recurrence after Surgery for Nonmetastatic Nonfunctional Neuroendocrine Neoplasm of the Pancreas.

Nodal involvement (actually categorized as positive or negative) is an important prognostic factor after surgery for pancreatic neuroendocrine neoplasms (pNENs). We aim to evaluate the predictive role of the number of nodal metastases after pancreatic resection for pNENs. We analyzed from a prospectively maintained database all pancreatic resections for nonmetastatic nonfunctioning pNENs performed in our institution from 2011 to 2016. According to the number of nodal metastases, enhancing the actual categorization, we distinguished the following: N0, no nodal metastases; N1, 1-3 metastatic lymph nodes; and N2, metastases in 4 or more regional lymph nodes. Recurrence and disease-free survival (DFS) were evaluated. The predictive value in terms of recurrence for each clinicopathological data, including the number of metastatic lymph nodes, was calculated. Univariate and multivariate analyses were conducted. 77 patients underwent pancreatic surgery for pNENs. N0, N1, and N2 resections were found in 52 (67.5%), 16 (20.8%), and 9 (11.7%) cases, respectively. Mean follow-up of the entire cohort was 48 (±25) months. The recurrence rate was 11.8%, and the mean time of recurrence was 12 (±14) months. DFS was 83.7 months (76.0 - 91.5). At a univariate analysis, factors associated with recurrence were mitotic count (OR 1.19, p = 0.001), Ki67 value (OR 1.06, p = 0.001), the presence of nodal metastases (OR 11.54, p = 0.002), and metastases in 4 or more regional lymph nodes (N2) (OR 30.19, p = 0.002). At a multivariate analysis, only mitotic count (OR 1.51, p = 0.005) and N2 resection (OR 134.74, p = 0.002) were found to be predictive factors of recurrence. The number of metastatic lymph nodes and mitotic count is the most significant predictive factors of recurrence after pancreatic surgery for nonmetastatic nonfunctioning pNENs.

The immunosuppressive cytokine interleukin-4 increases the clonogenic potential of prostate stem-like cells by activation of STAT6 signalling.

Interleukin-4 plays a critical role in the regulation of immune responses and has been detected at high levels in the tumour microenvironment of cancer patients, where concentrations correlate with the grade of malignancy. In prostate cancer, interleukin-4 has been associated with activation of the androgen receptor, increased proliferation and activation of survival pathways such as Akt and NF-κB. However, its role in therapy resistance has not yet been determined. Here we investigate the influence of interleukin-4 on primary epithelial cells from prostate cancer patients. Our data demonstrate an increase in the clonogenic potential of these cells when cultured in the presence of interleukin-4. In addition, a Phospho-Kinase Array revealed that in contrast to previously published work, signal transducer and activator of transcription6 (STAT6) is the only signalling molecule activated after interleukin-4 treatment. Using the STAT6-specific inhibitor AS1517499 we could confirm the role of STAT6 in increasing colony-forming frequency. However, clonogenic recovery assays revealed that interleukin-4 does not rescue the effects of either irradiation or docetaxel treatment. We therefore propose that although the interleukin-4/STAT6 axis does not appear to be involved in therapy resistance, it does play a crucial role in the colony-forming abilities of the basal cell population in prostate cancer. IL-4 may therefore contribute to disease relapse by providing a niche that is favourable for the clonogenic growth of prostate cancer stem cells.

Surgical margins for duodenopancreatectomy.

Microscopic residual tumor (R1) affects prognosis of resected pancreatic head cancer patients. Surgeon's ability, caseload and accuracy of pathological staging affect the rate of R1 resections. The goal of this study was to verify if a standardized histopathological workup of the specimen affects the rate of microscopic residual tumor after PD for cancer. Two groups of specimens were managed with (Group 1, Standardized Group, SG) or without (Group 2, Non Standardized Group, NSG) a standardized histopathological workup reported by the Royal College of Pathologists. Group 1 included 50 cases of PD for periampullary cancer treated between October 2010 and July 2012. Group 2 included 50 cases of PD for periampullary cancer treated between September 2005 and September 2010. The primary endpoint of the study was to verify the differences in terms of R1 rate in the two groups. Correlation between presence/absence of microscopic residual tumor status and local recurrence was also evaluated. The cohort of 100 patients consisted of 66 pancreatic ductal adenocarcinoma (PDAC) (SG: 35; NSG: 31), 15 distal common bile duct cancer (SG: 9; NSG: 6) and 19 cancer of the ampulla of Vater (SG: 6; NSG: 13). The rate of R1 resections resulted higher in the SG (66% vs 10%, p < 0.05). The rate of local recurrence did not differ in the two groups (NSG 23.4%, SG 27.6%). No relationships were found between R1 status and development of local recurrence in both groups. Local recurrence occurred in 20% of R1-NSG and in 34.3% of R1-SG. Our study showed that the standardized method determines a significant increase of R1 resection if compared with other non-standardized methods. This difference is due to the different definition of minimum clearance (0-mm- vs 1-mm rule). Even if not significantly, the standardized method seems to better discriminate the patients in terms of local recurrence risk after R1 vs R0 in SG (34 vs 11%) in comparison with R1 vs R0 in NSG (20 vs 27%).

FK506 binding protein 51 positively regulates melanoma stemness and metastatic potential.

Melanoma is the most aggressive skin cancer; there is no cure in advanced stages. Identifying molecular participants in melanoma progression may provide useful diagnostic and therapeutic tools. FK506 binding protein 51 (FKBP51), an immunophilin with a relevant role in developmental stages, is highly expressed in melanoma and correlates with aggressiveness and therapy resistance. We hypothesized a role for FKBP51 in melanoma invasive behaviour. FKBP51 promoted activation of epithelial-to-mesenchymal transition (EMT) genes and improved melanoma cell migration and invasion. In addition, FKBP51 induced some melanoma stem cell (MCSC) genes. Purified MCSCs expressed high EMT genes levels, suggesting that genetic programs of EMT and MCSCs overlap. Immunohistochemistry of samples from patients showed intense FKBP51 nuclear signal and cytoplasmic positivity for the stem cell marker nestin in extravasating melanoma cells and metastatic brains. In addition, FKBP51 targeting by small interfering RNA (siRNA) prevented the massive metastatic substitution of liver and lung in a mouse model of experimental metastasis. The present study provides evidence that the genetic programs of cancer stemness and invasiveness overlap in melanoma, and that FKBP51 plays a pivotal role in sustaining such a program.

The emerging role of large immunophilin FK506 binding protein 51 in cancer.

FK506 binding protein 51 (FKBP51) is an immunophilin physiologically expressed in lymphocytes. Very recently, aberrant expression of this protein was found in melanoma; FKBP51 expression correlates with melanoma aggressiveness and is maximal in metastatic lesions. FKBP51 promotes NF-κB activation and is involved in the resistance to genotoxic agents, including anthracyclines and ionizing radiation. FKBP51 is a cochaperone with peptidyl-prolyl isomerase activity that regulates several biological processes through protein-protein interaction. There is increasing evidence that FKBP51 hyperexpression is associated with cancer and this protein has a relevant role in sustaining cell growth, malignancy, and resistance to therapy. There is also evidence that FKBP ligands are potent anticancer agents, in addition to their immunosuppressant activity. In particular, rapamycin and its analogs have shown antitumor activity across a variety of human cancers in clinical trials. Although, classically, rapamycin actions are ascribed to inhibition of mTOR, recent studies indicate FKBP51 is also an important molecular determinant of the drug's anticancer activity. The aim of this article is to review the functions of FKBP51, especially in view of the recent findings that this protein is a potential oncogene when deregulated and a candidate target for signaling therapies against cancer.