Objective:To investigate the clinical characteristics and prognosis of follicular lymphoma (FL) patients with different primary sites using the Surveillance, Epidemiology, and End Results (SEER) database.Methods:Clinical data of 7167 patients with early-stage FL (stage I-II) from the SEER database between 2000 and 2015 were respectively analyzed. Primary sites were divided into intranodal and extranodal types. Intranodal primary sites included supradiaphragmatic lymph nodes (LN), subphrenic lymph nodes and Waldeyer's ring. Extranodal primary sites consisted of skin, gastrointestinal tract, duodenum, head and neck, other sites. Prognostic factors and overall survival (OS) in patients with different primary sites were analyzed. OS rate was evaluated using Kaplan-Meier method and survival difference between primary sites was compared with log-rank test. Inverse probability treatment weighting (IPTW) and multi-variable analysis were applied to adjust for confounding factors. Multivariate Cox regression analysis of influencing factors of OS was performed.Results:The median age was 63 years old, with the median follow-up time of 63 months. There was no difference in prognosis among the intranodal groups or between the intranodal and extranodal groups. The 10-year OS rates of the supradiaphragmatic lymph LN ( n=2146), subdiaphragmatic LN ( n=2811), and the Waldeyer's ring ( n=151) groups were 70.7%, 69.9% and 73.4%, respectively ( P=0.422 for infradiaphragmatic LN vs. supradiaphragmatic LN, P=1.000 for Waldeyer's ring vs. supradiaphragmatic LN), and 70.3% and 68.9% for intranodal ( n=5108) and extranodal ( n=2059), respectively. There was no significant difference in OS between the groups ( P=0.581) after IPTW adjustment. The most common primary sites in extranodal disease were skin, gastrointestinal tract, head and neck, and duodenum. The 10-year OS for skin, gastrointestinal tract, and cutaneous was 74.2%, 74.7%, and 87.3%, respectively, significantly higher than 55.6% for other sites (duodenum vs. others sites, gastrointestinal vs. others sites, skin vs. others sites: all P<0.001). Multivariate Cox regression analysis revealed that difference in OS was not significant among the intranodal groups or between the intranodal and extranodal groups. However, different extranodal primary site was an independent prognostic factor for OS. Conclusions:Early FL patients with supradiaphragmatic LN, subdiaphragmatic LN and Waldeyer's ring, and between the intranodal and extranodal primary sites obtain similar prognosis. However, early-stage FL patients with different extranodal primary sites have prognostic differences. The prognosis of primary skin, gastrointestinal tract and duodenum is significantly better than that of other extranodal primary sites.

Objective:To investigate the clinical characteristics and prognosis of follicular lymphoma (FL) patients with different primary sites using the Surveillance, Epidemiology, and End Results (SEER) database.Methods:Clinical data of 7167 patients with early-stage FL (stage I-II) from the SEER database between 2000 and 2015 were respectively analyzed. Primary sites were divided into intranodal and extranodal types. Intranodal primary sites included supradiaphragmatic lymph nodes (LN), subphrenic lymph nodes and Waldeyer's ring. Extranodal primary sites consisted of skin, gastrointestinal tract, duodenum, head and neck, other sites. Prognostic factors and overall survival (OS) in patients with different primary sites were analyzed. OS rate was evaluated using Kaplan-Meier method and survival difference between primary sites was compared with log-rank test. Inverse probability treatment weighting (IPTW) and multi-variable analysis were applied to adjust for confounding factors. Multivariate Cox regression analysis of influencing factors of OS was performed.Results:The median age was 63 years old, with the median follow-up time of 63 months. There was no difference in prognosis among the intranodal groups or between the intranodal and extranodal groups. The 10-year OS rates of the supradiaphragmatic lymph LN ( n=2146), subdiaphragmatic LN ( n=2811), and the Waldeyer's ring ( n=151) groups were 70.7%, 69.9% and 73.4%, respectively ( P=0.422 for infradiaphragmatic LN vs. supradiaphragmatic LN, P=1.000 for Waldeyer's ring vs. supradiaphragmatic LN), and 70.3% and 68.9% for intranodal ( n=5108) and extranodal ( n=2059), respectively. There was no significant difference in OS between the groups ( P=0.581) after IPTW adjustment. The most common primary sites in extranodal disease were skin, gastrointestinal tract, head and neck, and duodenum. The 10-year OS for skin, gastrointestinal tract, and cutaneous was 74.2%, 74.7%, and 87.3%, respectively, significantly higher than 55.6% for other sites (duodenum vs. others sites, gastrointestinal vs. others sites, skin vs. others sites: all P<0.001). Multivariate Cox regression analysis revealed that difference in OS was not significant among the intranodal groups or between the intranodal and extranodal groups. However, different extranodal primary site was an independent prognostic factor for OS. Conclusions:Early FL patients with supradiaphragmatic LN, subdiaphragmatic LN and Waldeyer's ring, and between the intranodal and extranodal primary sites obtain similar prognosis. However, early-stage FL patients with different extranodal primary sites have prognostic differences. The prognosis of primary skin, gastrointestinal tract and duodenum is significantly better than that of other extranodal primary sites.

ERIC-PCR has been widely used as genomic fingerprinting technology for classification and identification of bacterial isolates. Recently, it has been used by some labs to characterize bacterial mixtures. However, there are still disputes regarding the mechanism of product formation in ERIC-PCR. We cloned and sequenced the 1. 1kb major band of the ERIC-PCR fingerprint of E. coli K-12 strain MG1655, the strain used for whole genome sequencing, and found that the band consisted of 3 different DNA fragments with one fragment the most abundant (93 out of 95 clones, i. e. 97. 89%). Sequence analysis showed that two of the three fragments amplified from a chromosomal region where one ERIC element exist either upstream or downstream, while one fragment amplified from a region where no ERIC element was found. It was thus postulated that ERIC-PCR is not an absolutely random amplified PCR technique, especially when it is applied to those genomes containing ERIC elements.