Purpose
Pathological complete response (pCR) following neoadjuvant chemoradiotherapy or radiotherapy in locally advanced rectal cancer (LARC) is reached in approximately 15–30% of cases, therefore it ...would be useful to assess if pretreatment of
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F-FDG PET/CT and/or MRI texture features can reliably predict response to neoadjuvant therapy in LARC.
Methods
Fifty-two patients were dichotomized as responder (pR+) or non-responder (pR-) according to their pathological tumor regression grade (TRG) as follows: 22 as pR+ (nine with TRG = 1, 13 with TRG = 2) and 30 as pR- (16 with TRG = 3, 13 with TRG = 4 and 1 with TRG = 5). First-order parameters and 21 second-order texture parameters derived from the Gray-Level Co-Occurrence matrix were extracted from semi-automatically segmented tumors on T2w MRI, ADC maps, and PET/CT acquisitions. The role of each texture feature in predicting pR+ was assessed with monoparametric and multiparametric models.
Results
In the mono-parametric approach, PET homogeneity reached the maximum AUC (0.77; sensitivity = 72.7% and specificity = 76.7%), while PET glycolytic volume and ADC dissimilarity reached the highest sensitivity (both 90.9%). In the multiparametric analysis, a logistic regression model containing six second-order texture features (five from PET and one from T2w MRI) yields the highest predictivity in distinguish between pR+ and pR- patients (AUC = 0.86; sensitivity = 86%, and specificity = 83% at the Youden index).
Conclusions
If preliminary results of this study are confirmed, pretreatment PET and MRI could be useful to personalize patient treatment, e.g., avoiding toxicity of neoadjuvant therapy in patients predicted pR-.
Pathological complete response (pCR) following neoadjuvant chemoradiotherapy or radiotherapy in locally advanced rectal cancer (LARC) is reached in approximately 15-30% of cases, therefore it would ...be useful to assess if pretreatment of
F-FDG PET/CT and/or MRI texture features can reliably predict response to neoadjuvant therapy in LARC.
Fifty-two patients were dichotomized as responder (pR+) or non-responder (pR-) according to their pathological tumor regression grade (TRG) as follows: 22 as pR+ (nine with TRG = 1, 13 with TRG = 2) and 30 as pR- (16 with TRG = 3, 13 with TRG = 4 and 1 with TRG = 5). First-order parameters and 21 second-order texture parameters derived from the Gray-Level Co-Occurrence matrix were extracted from semi-automatically segmented tumors on T2w MRI, ADC maps, and PET/CT acquisitions. The role of each texture feature in predicting pR+ was assessed with monoparametric and multiparametric models.
In the mono-parametric approach, PET homogeneity reached the maximum AUC (0.77; sensitivity = 72.7% and specificity = 76.7%), while PET glycolytic volume and ADC dissimilarity reached the highest sensitivity (both 90.9%). In the multiparametric analysis, a logistic regression model containing six second-order texture features (five from PET and one from T2w MRI) yields the highest predictivity in distinguish between pR+ and pR- patients (AUC = 0.86; sensitivity = 86%, and specificity = 83% at the Youden index).
If preliminary results of this study are confirmed, pretreatment PET and MRI could be useful to personalize patient treatment, e.g., avoiding toxicity of neoadjuvant therapy in patients predicted pR-.
The tunica propria of seminiferous tubules contains a particular type of smooth muscle cell (myoid cells) arranged in a contractile epithelioid layer that is responsible for sperm and tubular fluid ...flow. Unlike other types of smooth muscle (SM) cells, highly purified populations of peritubular smooth muscle cells (PSMC) survive and maintain their contractile phenotype in primary cultures in controlled conditions. We used this culture model to investigate the response of the SM contractile phenotype to prolonged exposure to platelet-derived growth factor (PDGF), one of the main factors involved in vascular SM pathologies. We observed that 4-day continuous exposure of PSMC to PDGF-BB at nanomolar concentrations in plain medium enhances contractile phenotype traits and induces cell hypertrophy without inducing proliferation. In Northern and Western blotting experiments, SM-alpha-actin transcript and protein were found to be markedly increased in the PDGF-BB-treated samples, which is in line with the formation of conspicuous SM-alpha-actin-containing stress fibers. Moreover, binding sites for endothelin-1 were increased, and the calcium response to the contractile agonist, determined in single fura-2-loaded cells, was enhanced. In response to PDGF-BB, the cells underwent immediate, transient contraction, as seen in a scanning electron microscope, followed by a gradual increase in size, as evaluated by cytofluorometry, and enhancement of protein synthesis. The observed pattern of response to PDGF-BB was not accompanied by cell proliferation, as assessed by 3Hthymidine incorporation and direct cell counts. Unlike other SM cell types, in which proliferation and loss of contractile traits are induced by PDGF, chronic treatment of PSMC with this growth factor results in hypertrophy rather than hyperplasia.
Since peritubular smooth muscle cells (PSMCs) have been characterized, isolated and cultured in homogeneous populations, the regulation of seminiferous epithelium contractility has received ...increasing attention. The present article reports and discusses experimental evidence demonstrating that: (1) PSMCs express two types of high affinity receptors for endothelin (ET-A and ET-B), both responsible for calcium-mediated cell contraction, but coupled to partially different transduction pathways; (2) the production of endothelin by seminiferous epithelium follows a finely regulated spatial and temporal pattern, which is based on the cyclic expression of endothelin-converting-enzyme in Sertoli cells; and (3) a further local factor, PDGF-BB, is capable of stimulating PSMC contraction when acutely administered and induces cell hypertrophy and potentiation of contractile phenotype when chronically administered, in the absence of any proliferative response. The study of the mechanisms through which PSMC contractile activity and differentiated state is locally controlled may be of potential relevance to our knowledge of how the efficiency of tubular output is regulated in normal and pathological conditions.
The possibility of diagnosing neoplastic testis pathologies by studying immature germ cells released from the seminiferous epithelium and present in the semen has been reported. It has been suggested ...that carcinoma in situ (CIS) of the testis and testis tumor may be identified by studying specific surface antigenic determinants or ploidy of chromosome 1 of malignant germ cells recovered from the semen. A noninvasive diagnostic approach of this type would be of great interest if we consider that CIS is supposed to precede the development of testicular germ cell tumors and that the frequency of that preneoplastic condition is increased in specific andrologic pathologies. To evaluate the reliability of this diagnostic approach, we have quantified the presence of immature hyperdiploid germ cells in the seminal fluid of normal healthy subjects, of infertile oligozoospermic patients affected by maldescended testis or left vancocele, and of patients suffering from CIS or testis tumor. Cell ploidy was evaluated on seminal cell fractions highly enriched in immature germ cells, by means of in situ hybridization with a DNA-probe specific for chromosome 1. Our observations indicate that chromosome 1 hyperdiploidy is not necessarily a predictive parameter of testis tumoral pathologies. The percentage of hyperdiploid immature seminal germ cells is in fact increased in nontumoral pathologies associated with infertility, such as cryptorchidism and left varicocele.
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